Html 简明教程
HTML - Overview
HTML代表*超文本*标记*语言，它是编写网页的最广泛使用的语言。
HTML stands for *H*yper*t*ext *M*arkup *L*anguage, and it is the most widely used language to write Web Pages.
-
Hypertext refers to the way in which Web pages (HTML documents) are linked together. Thus, the link available on a webpage is called Hypertext.
-
As its name suggests, HTML is a Markup Language which means you use HTML to simply "mark-up" a text document with tags that tell a Web browser how to structure it to display.
最初，HTML的开发旨在定义文档（如标题、段落、列表等）的结构，以促进研究人员之间共享科学信息。
Originally, HTML was developed with the intent of defining the structure of documents like headings, paragraphs, lists, and so forth to facilitate the sharing of scientific information between researchers.
现在，HTML被广泛用于通过HTML语言中提供的不同标签对网页进行格式化。
Now, HTML is being widely used to format web pages with the help of different tags available in HTML language.
Basic HTML Document
在其最简单的形式中，下面是一个HTML文档的示例 -
In its simplest form, following is an example of an HTML document −
<!DOCTYPE html>
<html>
<head>
<title>This is document title</title>
</head>
<body>
<h1>This is a heading</h1>
<p>Document content goes here.....</p>
</body>
</html>HTML Tags
如前所述，HTML是一种标记语言，并使用各种标签来格式化内容。这些标记被括在尖括号 <Tag Name> 中。除了少数标签之外，大多数标签都有其对应的关闭标签。例如， <html> 有其关闭标签 </html> ， <body> 标签有其关闭标签 </body> 标签等。
As told earlier, HTML is a markup language and makes use of various tags to format the content. These tags are enclosed within angle braces <Tag Name>. Except few tags, most of the tags have their corresponding closing tags. For example, <html> has its closing tag </html> and <body> tag has its closing tag </body> tag etc.
上述HTML文档示例使用了以下标签 -
Above example of HTML document uses the following tags −
Sr.No |
Tag & Description |
1 |
*<!DOCTYPE…>*This tag defines the document type and HTML version. |
2 |
*<html>*This tag encloses the complete HTML document and mainly comprises of document header which is represented by <head>…</head> and document body which is represented by <body>…</body> tags. |
3 |
*<head>*This tag represents the document’s header which can keep other HTML tags like <title>, <link> etc. |
4 |
*<title>*The <title> tag is used inside the <head> tag to mention the document title. |
5 |
*<body>*This tag represents the document’s body which keeps other HTML tags like <h1>, <div>, <p> etc. |
6 |
*<h1>*This tag represents the heading. |
7 |
*<p>*This tag represents a paragraph. |
要学习HTML，您需要研究各种标签并了解它们的行为，同时格式化文本文档。学习HTML很简单，因为用户必须学习使用不同的标签来格式化文本或图像以制作漂亮的网页。
To learn HTML, you will need to study various tags and understand how they behave, while formatting a textual document. Learning HTML is simple as users have to learn the usage of different tags in order to format the text or images to make a beautiful webpage.
万维网联盟（W3C）建议从HTML 4开始使用小写标签。
World Wide Web Consortium (W3C) recommends to use lowercase tags starting from HTML 4.
HTML Document Structure
一个典型的HTML文档将具有以下结构 -
A typical HTML document will have the following structure −
<html>
<head>
Document header related tags
</head>
<body>
Document body related tags
</body>
</html>我们将在后续章节中学习所有标题和正文标签，但现在让我们看看什么是文档声明标签。
We will study all the header and body tags in subsequent chapters, but for now let’s see what is document declaration tag.
The <!DOCTYPE> Declaration
浏览器使用 <!DOCTYPE> 声明标记来理解文档中使用的 HTML 版本。当前 HTML 版本为 5，它使用以下声明 −
The <!DOCTYPE> declaration tag is used by the web browser to understand the version of the HTML used in the document. Current version of HTML is 5 and it makes use of the following declaration −
<!DOCTYPE html>根据所使用的 HTML 版本，HTML 文档中还可以使用许多其它声明类型。在讨论 <!DOCTYPE…> 标记和其它 HTML 标记时，我们将详细介绍此内容。
There are many other declaration types which can be used in HTML document depending on what version of HTML is being used. We will see more details on this while discussing <!DOCTYPE…> tag along with other HTML tags.
HTML - Basic Tags
Heading Tags
任何文档都以标题开头。您可以对标题使用不同的尺寸。HTML 还有六个级别的标题，它们使用元素 <h1>, <h2>, <h3>, <h4>, <h5>, 和 <h6> 。在显示任何标题时，浏览器将在这标题前面和后面各添加一行。
Any document starts with a heading. You can use different sizes for your headings. HTML also has six levels of headings, which use the elements <h1>, <h2>, <h3>, <h4>, <h5>, and <h6>. While displaying any heading, browser adds one line before and one line after that heading.
Example
<!DOCTYPE html>
<html>
<head>
<title>Heading Example</title>
</head>
<body>
<h1>This is heading 1</h1>
<h2>This is heading 2</h2>
<h3>This is heading 3</h3>
<h4>This is heading 4</h4>
<h5>This is heading 5</h5>
<h6>This is heading 6</h6>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Paragraph Tag
<p> 标记提供了一种将文本构建成不同段落的方法。每一段文本都应该放在一个开始的 <p> 和一个结束的 </p> 标记之间，如下例中所示 −
The <p> tag offers a way to structure your text into different paragraphs. Each paragraph of text should go in between an opening <p> and a closing </p> tag as shown below in the example −
Line Break Tag
每当您使用 <br /> 元素时，跟随它的任何内容都将从下一行开始。此标记是 empty 元素的一个示例，其中您不需要开始和结束标记，因为它们之间没有任何内容。
Whenever you use the <br /> element, anything following it starts from the next line. This tag is an example of an empty element, where you do not need opening and closing tags, as there is nothing to go in between them.
<br /> 标记在字符 br 和正斜杠之间有一个空格。如果您省略此空格，旧版浏览器将难以呈现换行符，而如果您错过了正斜杠字符并仅使用 <br>，则它在 XHTML 中无效。
The <br /> tag has a space between the characters br and the forward slash. If you omit this space, older browsers will have trouble rendering the line break, while if you miss the forward slash character and just use <br> it is not valid in XHTML.
Centering Content
您可以使用 <center> 标记将任何内容放在页面或任何表格单元格的中心。
You can use <center> tag to put any content in the center of the page or any table cell.
Horizontal Lines
水平线用于在视觉上打断文档的部分内容。 <hr> 标记从文档中的当前位置创建一个行至右侧边距并相应地中断该行。
Horizontal lines are used to visually break-up sections of a document. The <hr> tag creates a line from the current position in the document to the right margin and breaks the line accordingly.
例如，您可能希望在两个段落之间添加一行，如下面的示例所示 −
For example, you may want to give a line between two paragraphs as in the given example below −
Example
<!DOCTYPE html>
<html>
<head>
<title>Horizontal Line Example</title>
</head>
<body>
<p>This is paragraph one and should be on top</p>
<hr />
<p>This is paragraph two and should be at bottom</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
再一次 <hr /> 标记是 empty 元素的示例，其中您不需要开始和结束标记，因为它们之间没有任何内容。
Again <hr /> tag is an example of the empty element, where you do not need opening and closing tags, as there is nothing to go in between them.
<hr /> 元素在字符 hr 和正斜杠之间有一个空格。如果您省略此空格，旧版浏览器将难以呈现水平线，而如果您错过了正斜杠字符并仅使用 <hr> ，则它在 XHTML 中无效
The <hr /> element has a space between the characters hr and the forward slash. If you omit this space, older browsers will have trouble rendering the horizontal line, while if you miss the forward slash character and just use <hr> it is not valid in XHTML
Preserve Formatting
有时，您希望文本遵循编写在 HTML 文档中的确切格式。在这些情况下，您可以使用预格式文本标签 <pre> 。
Sometimes, you want your text to follow the exact format of how it is written in the HTML document. In these cases, you can use the preformatted tag <pre>.
开始 <pre> 标记和结束 </pre> 标记之间的任何文本都将保留源文档的格式。
Any text between the opening <pre> tag and the closing </pre> tag will preserve the formatting of the source document.
Example
<!DOCTYPE html>
<html>
<head>
<title>Preserve Formatting Example</title>
</head>
<body>
<pre>
function testFunction( strText ){
alert (strText)
}
</pre>
</body>
</html>这会产生以下结果 −
This will produce the following result −
尝试使用相同的代码而不用于 <pre>…</pre> 标记中
Try using the same code without keeping it inside <pre>…</pre> tags
Nonbreaking Spaces
假设您想使用短语“12 Angry Men”。在这里，您不希望浏览器将“12, Angry”和“Men”分隔在两行上 −
Suppose you want to use the phrase "12 Angry Men." Here, you would not want a browser to split the "12, Angry" and "Men" across two lines −
An example of this technique appears in the movie "12 Angry Men."在您不希望客户端浏览器中断文本的情况下，您应该使用不间断空格实体 * * 来代替正常空格。例如，在段落中编码“12 Angry Men”时，您应该使用类似于以下代码的内容 −
In cases, where you do not want the client browser to break text, you should use a nonbreaking space entity * * instead of a normal space. For example, when coding the "12 Angry Men" in a paragraph, you should use something similar to the following code −
HTML - Elements
一个 HTML element 由一个开始的标记定义。如果此元素包含其他内容，则它将以一个结束的标记结束，在其中元素名称之前有一个正斜杠，如下所示，带有一些标记 −
An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag, where the element name is preceded by a forward slash as shown below with few tags −
Start Tag |
Content |
End Tag |
<p> |
This is paragraph content. |
</p> |
<h1> |
This is heading content. |
</h1> |
<div> |
This is division content. |
</div> |
<br /> |
因此这里的 <p>….</p> 是一个 HTML 元素， <h1>…</h1> 是另一个 HTML 元素。有一些 HTML 元素不需要闭合，例如 <img…/> 、 <hr /> 和 <br /> 元素。这些元素被称为 void elements 。
So here <p>….</p> is an HTML element, <h1>…</h1> is another HTML element. There are some HTML elements which don’t need to be closed, such as <img…/>, <hr /> and <br /> elements. These are known as void elements.
HTML 文档由这些元素的树组成，它们指定了 HTML 文档的构建方式，以及应该在 HTML 文档的哪一部分放置什么内容。
HTML documents consists of a tree of these elements and they specify how HTML documents should be built, and what kind of content should be placed in what part of an HTML document.
HTML Tag vs. Element
HTML 元素由起始标记定义。如果该元素包含其他内容，则以结束标记结尾。
An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag.
例如， <p> 是段落的起始标记，且 </p> 是同一段落的结束标记，但 <p>This is paragraph</p> 是一个段落元素。
For example, <p> is starting tag of a paragraph and </p> is closing tag of the same paragraph but <p>This is paragraph</p> is a paragraph element.
HTML - Attributes
我们已经看到了几个 HTML 标记及其使用方法，如标题标记 <h1>, <h2>, 段落标记 <p> 和其他标记。我们到目前为止以最简单的形式使用它们，但大多数 HTML 标记也可以有属性，这是额外的信息片段。
We have seen few HTML tags and their usage like heading tags <h1>, <h2>, paragraph tag <p> and other tags. We used them so far in their simplest form, but most of the HTML tags can also have attributes, which are extra bits of information.
属性用于定义 HTML 元素的特性，并放置在元素的开始标记中。所有属性都由两部分组成− name 和 value
An attribute is used to define the characteristics of an HTML element and is placed inside the element’s opening tag. All attributes are made up of two parts − a name and a value
-
The name is the property you want to set. For example, the paragraph <p> element in the example carries an attribute whose name is align, which you can use to indicate the alignment of paragraph on the page.
-
The value is what you want the value of the property to be set and always put within quotations. The below example shows three possible values of align attribute: * left, center* and right.
属性名称和属性值不区分大小写。然而，万维网联盟 (W3C) 在其 HTML 4 建议中推荐使用小写属性/属性值。
Attribute names and attribute values are case-insensitive. However, the World Wide Web Consortium (W3C) recommends lowercase attributes/attribute values in their HTML 4 recommendation.
Example
<!DOCTYPE html>
<html>
<head>
<title>Align Attribute Example</title>
</head>
<body>
<p align = "left">This is left aligned</p>
<p align = "center">This is center aligned</p>
<p align = "right">This is right aligned</p>
</body>
</html>这将显示以下结果−
This will display the following result −
Core Attributes
可以在大多数 HTML 元素上使用（虽然并非全部）的四个核心属性为−
The four core attributes that can be used on the majority of HTML elements (although not all) are −
-
Id
-
Title
-
Class
-
Style
The Id Attribute
HTML 标记的 id 属性可用于唯一识别 HTML 页面中的任何元素。你可能希望在元素上使用 id 属性有两个主要原因−
The id attribute of an HTML tag can be used to uniquely identify any element within an HTML page. There are two primary reasons that you might want to use an id attribute on an element −
-
If an element carries an id attribute as a unique identifier, it is possible to identify just that element and its content.
-
If you have two elements of the same name within a Web page (or style sheet), you can use the id attribute to distinguish between elements that have the same name.
我们将在单独的教程中讨论样式表。现在，让我们使用 id 属性区分两个段落元素，如下所示：
We will discuss style sheet in separate tutorial. For now, let’s use the id attribute to distinguish between two paragraph elements as shown below.
Example
<p id = "html">This para explains what is HTML</p>
<p id = "css">This para explains what is Cascading Style Sheet</p>The title Attribute
title 属性为元素提供建议名称。 title 属性的语法类似于对 id 属性的解释−
The title attribute gives a suggested title for the element. They syntax for the title attribute is similar as explained for id attribute −
此属性的行为将取决于携带它的元素，尽管通常在光标移至元素上方或元素加载时显示为工具提示。
The behavior of this attribute will depend upon the element that carries it, although it is often displayed as a tooltip when cursor comes over the element or while the element is loading.
Example
<!DOCTYPE html>
<html>
<head>
<title>The title Attribute Example</title>
</head>
<body>
<h3 title = "Hello HTML!">Titled Heading Tag Example</h3>
</body>
</html>这会产生以下结果 −
This will produce the following result −
现在尝试将你的光标移到“有标题的标题标签示例”上，你将看到你在代码中使用的任何标题都作为光标的工具提示显示出来。
Now try to bring your cursor over "Titled Heading Tag Example" and you will see that whatever title you used in your code is coming out as a tooltip of the cursor.
The class Attribute
class 属性用于将元素与样式表关联，并指定元素的类。当你学习层叠样式表 (CSS) 时，你将更多地了解类属性的使用。所以现在你可以避免它。
The class attribute is used to associate an element with a style sheet, and specifies the class of element. You will learn more about the use of the class attribute when you will learn Cascading Style Sheet (CSS). So for now you can avoid it.
该属性的值也可以是类名空格分隔的列表。例如−
The value of the attribute may also be a space-separated list of class names. For example −
class = "className1 className2 className3"The style Attribute
style 属性允许你在元素内指定层叠样式表 (CSS) 规则。
The style attribute allows you to specify Cascading Style Sheet (CSS) rules within the element.
<!DOCTYPE html>
<html>
<head>
<title>The style Attribute</title>
</head>
<body>
<p style = "font-family:arial; color:#FF0000;">Some text...</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
目前，我们不学习 CSS，因此让我们在不必过多了解 CSS 的情况下继续学习吧。在这里，你需要了解 HTML 属性是什么以及在设置内容格式时如何使用它们。
At this point of time, we are not learning CSS, so just let’s proceed without bothering much about CSS. Here, you need to understand what are HTML attributes and how they can be used while formatting content.
Internationalization Attributes
有三个国际化属性，可用于大多数 XHTML 元素（但不能用于所有）。
There are three internationalization attributes, which are available for most (although not all) XHTML elements.
-
dir
-
lang
-
xml:lang
The dir Attribute
dir 属性允许你向浏览器指示文本应流动的方向。dir 属性可以采用两个值之一，如下表所示 −
The dir attribute allows you to indicate to the browser about the direction in which the text should flow. The dir attribute can take one of two values, as you can see in the table that follows −
Value |
Meaning |
ltr |
Left to right (the default value) |
rtl |
Right to left (for languages such as Hebrew or Arabic that are read right to left) |
Example
<!DOCTYPE html>
<html dir = "rtl">
<head>
<title>Display Directions</title>
</head>
<body>
This is how IE 5 renders right-to-left directed text.
</body>
</html>这会产生以下结果 −
This will produce the following result −
当 dir 属性在 <html> 标签中使用时，它将确定文本将在整个文档中如何显示。当在其他标签中使用时，它将仅控制该标签内容的文本方向。
When dir attribute is used within the <html> tag, it determines how text will be presented within the entire document. When used within another tag, it controls the text’s direction for just the content of that tag.
The lang Attribute
lang 属性允许你指示文档中使用的主要语言，但此属性在 HTML 中仅保留用于向后兼容早期版本的 HTML。此属性已在新 XHTML 文档中被 xml:lang 属性取代。
The lang attribute allows you to indicate the main language used in a document, but this attribute was kept in HTML only for backwards compatibility with earlier versions of HTML. This attribute has been replaced by the xml:lang attribute in new XHTML documents.
lang 属性值是 ISO-639 标准的两位语言代码。有关语言代码完整列表，请访问 HTML Language Codes: ISO 639 。
The values of the lang attribute are ISO-639 standard two-character language codes. Check HTML Language Codes: ISO 639 for a complete list of language codes.
Example
<!DOCTYPE html>
<html lang = "en">
<head>
<title>English Language Page</title>
</head>
<body>
This page is using English Language
</body>
</html>这会产生以下结果 −
This will produce the following result −
The xml:lang Attribute
xml:lang 属性是用于替代 lang 属性的 XHTML。如前小节中所述，xml:lang 属性值应为 ISO-639 国家/地区代码。
The xml:lang attribute is the XHTML replacement for the lang attribute. The value of the xml:lang attribute should be an ISO-639 country code as mentioned in previous section.
Generic Attributes
以下是其他一些可与许多 HTML 标记一起使用的属性的表格。
Here’s a table of some other attributes that are readily usable with many of the HTML tags.
Attribute |
Options |
Function |
align |
right, left, center |
Horizontally aligns tags |
valign |
top, middle, bottom |
Vertically aligns tags within an HTML element. |
bgcolor |
numeric, hexidecimal, RGB values |
Places a background color behind an element |
background |
URL |
Places a background image behind an element |
id |
User Defined |
Names an element for use with Cascading Style Sheets. |
class |
User Defined |
Classifies an element for use with Cascading Style Sheets. |
width |
Numeric Value |
Specifies the width of tables, images, or table cells. |
height |
Numeric Value |
Specifies the height of tables, images, or table cells. |
title |
User Defined |
"Pop-up" title of the elements. |
随着对其他 HTML 标签的研究，我们将看到相关的示例。有关 HTML 标签和相关属性的完整列表，请参阅 HTML Tags List 。
We will see related examples as we will proceed to study other HTML tags. For a complete list of HTML Tags and related attributes please check reference to HTML Tags List.
HTML - Formatting
如果您使用文字处理器，您肯定熟悉加粗、斜体或下划线等文本编辑功能；这只是 HTML 和 XHTML 中表示文本显示方式的十种选项中的三种。
If you use a word processor, you must be familiar with the ability to make text bold, italicized, or underlined; these are just three of the ten options available to indicate how text can appear in HTML and XHTML.
Bold Text
显示在 <b>…</b> 元素中的任何内容都将显示为粗体，如下所示：
Anything that appears within <b>…</b> element, is displayed in bold as shown below −
Italic Text
显示在 <i>…</i> 元素中的任何内容都将显示为斜体，如下所示：
Anything that appears within <i>…</i> element is displayed in italicized as shown below −
Underlined Text
显示在 <u>…</u> 元素中的任何内容都将显示为下划线，如下所示：
Anything that appears within <u>…</u> element, is displayed with underline as shown below −
Strike Text
显示在 <strike>…</strike> 元素中的任何内容都将显示为删除线，即文本中插入一条细线，如下所示：
Anything that appears within <strike>…</strike> element is displayed with strikethrough, which is a thin line through the text as shown below −
Monospaced Font
<tt>…</tt> 元素的内容将以等宽字体显示。由于不同字母的宽度不同（例如字母“m”比字母“i”更宽），因此大多数字体称为变宽字体。但是，在等宽字体中，每个字母的宽度都相同。
The content of a <tt>…</tt> element is written in monospaced font. Most of the fonts are known as variable-width fonts because different letters are of different widths (for example, the letter 'm' is wider than the letter 'i'). In a monospaced font, however, each letter has the same width.
Superscript Text
<sup>…</sup> 元素的内容以上角标形式书写；使用的字体大小与周围的字符大小相同，但显示在其他字符上方半字符高度的位置处。
The content of a <sup>…</sup> element is written in superscript; the font size used is the same size as the characters surrounding it but is displayed half a character’s height above the other characters.
Subscript Text
<sub>…</sub> 元素的内容以下角标形式书写；使用的字体大小与周围的字符大小相同，但显示在其他字符下方半字符高度的位置处。
The content of a <sub>…</sub> element is written in subscript; the font size used is the same as the characters surrounding it, but is displayed half a character’s height beneath the other characters.
Inserted Text
处于 <ins>…</ins> 元素内的任何内容都显示为插入文本。
Anything that appears within <ins>…</ins> element is displayed as inserted text.
Deleted Text
处于 <del>…</del> 元素内的任何内容都显示为已删除的文本。
Anything that appears within <del>…</del> element, is displayed as deleted text.
Larger Text
处于 <big>…</big> 元素内的内容的显示字体比周围文本大一个字体大小，如下所示 −
The content of the <big>…</big> element is displayed one font size larger than the rest of the text surrounding it as shown below −
Smaller Text
处于 <small>…</small> 元素内的内容的显示字体比周围文本小一个字体大小，如下所示 −
The content of the <small>…</small> element is displayed one font size smaller than the rest of the text surrounding it as shown below −
Grouping Content
<div> 和 <span> 元素允许您将若干元素组合在一起，创建页面的节或小节。
The <div> and <span> elements allow you to group together several elements to create sections or subsections of a page.
例如，您可能希望将页面上的所有脚注都放在 <div> 元素内，以标记 <div> 元素内的所有元素都与脚注有关。然后，您可能会为此 <div> 元素附加一个样式，以便它们使用一组特殊样式规则显示。
For example, you might want to put all of the footnotes on a page within a <div> element to indicate that all of the elements within that <div> element relate to the footnotes. You might then attach a style to this <div> element so that they appear using a special set of style rules.
Example
<!DOCTYPE html>
<html>
<head>
<title>Div Tag Example</title>
</head>
<body>
<div id = "menu" align = "middle" >
<a href = "/index.htm">HOME</a> |
<a href = "/about/contact_us.htm">CONTACT</a> |
<a href = "/about/index.htm">ABOUT</a>
</div>
<div id = "content" align = "left" >
<h5>Content Articles</h5>
<p>Actual content goes here.....</p>
</div>
</body>
</html>这会产生以下结果 −
This will produce the following result −
另一方面，<span> 元素只能用于对行内元素进行分组。因此，如果您要对句子或段落的部分内容进行分组，可以使用 <span> 元素，如下所示。
The <span> element, on the other hand, can be used to group inline elements only. So, if you have a part of a sentence or paragraph which you want to group together, you could use the <span> element as follows.
Example
<!DOCTYPE html>
<html>
<head>
<title>Span Tag Example</title>
</head>
<body>
<p>This is the example of <span style = "color:green">span tag</span>
and the <span style = "color:red">div tag</span> alongwith CSS</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
这些标记通常与 CSS 一起使用，以便您可以为页面的某个节附加一个样式。
These tags are commonly used with CSS to allow you to attach a style to a section of a page.
HTML - Phrase Tags
短语标记已经过专门设计，以用于特定目的，尽管它们的显示方式与你在之前的章节中看到过的其他基本标记（如 <b>, <i>, <pre> 和 <tt> ）类似。本章将带你了解所有重要的短语标记，所以让我们逐一看看它们。
The phrase tags have been desicolgned for specific purposes, though they are displayed in a similar way as other basic tags like <b>, <i>, <pre>, and <tt>, you have seen in previous chapter. This chapter will take you through all the important phrase tags, so let’s start seeing them one by one.
Emphasized Text
处于 <em>…</em> 元素的内容显示为加重文本。
Anything that appears within <em>…</em> element is displayed as emphasized text.
Marked Text
处于 <mark>…</mark> 元素内显示的内容使用黄色墨水标记。
Anything that appears with-in <mark>…</mark> element, is displayed as marked with yellow ink.
Strong Text
处于 <strong>…</strong> 元素的内容显示为重要文本。
Anything that appears within <strong>…</strong> element is displayed as important text.
Text Abbreviation
您可以在开启 <abbr> 标记和关闭 </abbr> 标记之间放置文本，对其进行缩写。存在时，title 属性必须包含此完整描述，且仅包含此完整描述。
You can abbreviate a text by putting it inside opening <abbr> and closing </abbr> tags. If present, the title attribute must contain this full description and nothing else.
Acronym Element
<acronym> 元素允许您指示 <acronym> 和 </acronym> 标记之间的文本是一个缩略词。
The <acronym> element allows you to indicate that the text between <acronym> and </acronym> tags is an acronym.
-
目前，主要浏览器不会改变 <acronym> 元素的内容的外观。
At present, the major browsers do not change the appearance of the content of the <acronym> element.
Text Direction
<bdo>…</bdo> 元素代表双向重写，并用于重写当前文本方向。
The <bdo>…</bdo> element stands for Bi-Directional Override and it is used to override the current text direction.
Special Terms
<dfn>…</dfn> 元素（或 HTML 定义元素）允许您指定您正在引入一个特殊术语。它的用法类似于在一段文字中使用斜体字。
The <dfn>…</dfn> element (or HTML Definition Element) allows you to specify that you are introducing a special term. It’s usage is similar to italic words in the midst of a paragraph.
通常，您会在初次引入关键词时使用 <dfn> 元素。大多数最新浏览器将 <dfn> 元素的内容呈现在斜体字中。
Typically, you would use the <dfn> element the first time you introduce a key term. Most recent browsers render the content of a <dfn> element in an italic font.
Quoting Text
当您想引用来自其他来源的段落时，您应该在 <blockquote>…</blockquote> 标记之间放置引文。
When you want to quote a passage from another source, you should put it in between <blockquote>…</blockquote> tags.
<blockquote> 元素内的文本通常是从周围文本的左右边缘缩进的，有时使用斜体字。
Text inside a <blockquote> element is usually indented from the left and right edges of the surrounding text, and sometimes uses an italicized font.
Example
<!DOCTYPE html>
<html>
<head>
<title>Blockquote Example</title>
</head>
<body>
<p>The following description of XHTML is taken from the W3C Web site:</p>
<blockquote>XHTML 1.0 is the W3C's first Recommendation for XHTML,following on
from earlier work on HTML 4.01, HTML 4.0, HTML 3.2 and HTML 2.0.</blockquote>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Short Quotations
<q>…</q> 元素用于在句子中添加双引号时。
The <q>…</q> element is used when you want to add a double quote within a sentence.
Text Citations
如果你想引用文本，你可以通过将其放在一个开始 <cite> 标签和结束 </cite> 标签之间来指明引用来源。
If you are quoting a text, you can indicate the source placing it between an opening <cite> tag and closing </cite> tag
正如您在印刷品中所期望的那样，默认情况下，<cite> 元素的内容会以斜体字呈现。
As you would expect in a print publication, the content of the <cite> element is rendered in italicized text by default.
Computer Code
任何应出现在网页上的编程代码都应放在 <code>…</code> 标签内。通常，<code> 元素的内容将以等宽字体显示，就像大多数编程书中的代码一样。
Any programming code to appear on a Web page should be placed inside <code>…</code> tags. Usually the content of the <code> element is presented in a monospaced font, just like the code in most programming books.
Keyboard Text
当你谈论计算机时，如果你希望告诉读者输入一些文本，你可以使用 <kbd>…</kbd> 元素来指明应键入的内容，如同本示例所示。
When you are talking about computers, if you want to tell a reader to enter some text, you can use the <kbd>…</kbd> element to indicate what should be typed in, as in this example.
Programming Variables
此元素通常与 <pre> 和 <code> 元素结合使用，以指明该元素的内容是一个变量。
This element is usually used in conjunction with the <pre> and <code> elements to indicate that the content of that element is a variable.
Program Output
<samp>…</samp> 元素指明程序的示例输出、脚本等。它主要用于记录编程或编码概念时。
The <samp>…</samp> element indicates sample output from a program, and script etc. Again, it is mainly used when documenting programming or coding concepts.
HTML - Meta Tags
HTML 让你可以通过各种方式指定元数据——有关文档的其他重要信息。META 元素可用于包含描述 HTML 文档属性的名称/值对，如作者、过期日期、关键字列表、文档作者等。
HTML lets you specify metadata - additional important information about a document in a variety of ways. The META elements can be used to include name/value pairs describing properties of the HTML document, such as author, expiry date, a list of keywords, document author etc.
<meta> 标签用于提供此类附加信息。此标签是一个空元素，因此没有结束标签，但它在其属性中承载信息。
The <meta> tag is used to provide such additional information. This tag is an empty element and so does not have a closing tag but it carries information within its attributes.
在您的文档中，您可以根据想要保留在文档中的信息来包含一个或多个元标记，但一般来说，元标记不影响文档的外观，因此从外观的角度来看，无论您是否包含它们都无关紧要。
You can include one or more meta tags in your document based on what information you want to keep in your document but in general, meta tags do not impact physical appearance of the document so from appearance point of view, it does not matter if you include them or not.
Adding Meta Tags to Your Documents
您可以通过在文档头中放置<meta>标签来为您的网页添加元数据，此头由 <head> 和 </head> 标签表示。除了核心属性之外，元标记还可以具有以下属性：
You can add metadata to your web pages by placing <meta> tags inside the header of the document which is represented by <head> and </head> tags. A meta tag can have following attributes in addition to core attributes −
Sr.No |
Attribute & Description |
1 |
Name Name for the property. Can be anything. Examples include, keywords, description, author, revised, generator etc. |
2 |
content Specifies the property’s value. |
3 |
scheme Specifies a scheme to interpret the property’s value (as declared in the content attribute). |
4 |
http-equiv Used for http response message headers. For example, http-equiv can be used to refresh the page or to set a cookie. Values include content-type, expires, refresh and set-cookie. |
Specifying Keywords
您可以使用<meta>标签来指定与文档相关的重要的关键字，然后这些关键字将在您对网页编制索引以进行搜索时被搜索引擎使用。
You can use <meta> tag to specify important keywords related to the document and later these keywords are used by the search engines while indexing your webpage for searching purpose.
Example
以下是示例，此处我们将HTML、元标记、元数据添加为文档的相关关键词。
Following is an example, where we are adding HTML, Meta Tags, Metadata as important keywords about the document.
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Document Description
可以使用 <meta> 标记来对文档进行简短描述。搜索引擎在索引网页以为搜索目的而使用此内容。
You can use <meta> tag to give a short description about the document. This again can be used by various search engines while indexing your webpage for searching purpose.
Document Revision Date
可以使用 <meta> 标记来提供文档上次更新的时间信息。网络浏览器在刷新网页时可以使用此信息。
You can use <meta> tag to give information about when last time the document was updated. This information can be used by various web browsers while refreshing your webpage.
Example
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "revised" content = "Tutorialspoint, 3/7/2014" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>Document Refreshing
可以使用 <meta> 标记来指定一段时间，之后网页将自动刷新。
A <meta> tag can be used to specify a duration after which your web page will keep refreshing automatically.
Example
如果希望页面每 5 秒刷新一次，可以使用以下语法。
If you want your page keep refreshing after every 5 seconds then use the following syntax.
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "revised" content = "Tutorialspoint, 3/7/2014" />
<meta http-equiv = "refresh" content = "5" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>Page Redirection
可以使用 <meta> 标记将页面重定向到任何其他网页。如果希望在一定秒数后重定向页面，也可以指定时间段。
You can use <meta> tag to redirect your page to any other webpage. You can also specify a duration if you want to redirect the page after a certain number of seconds.
Example
以下是将当前页面在 5 秒后重定向到另一页面的示例。如果希望立即重定向页面，那么不要指定 content 属性。
Following is an example of redirecting current page to another page after 5 seconds. If you want to redirect page immediately then do not specify content attribute.
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "revised" content = "Tutorialspoint, 3/7/2014" />
<meta http-equiv = "refresh" content = "5; url = https://www.tutorialspoint.com" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>Setting Cookies
Cookie 是存储在计算机上的小型文本文件中的数据，它在Web浏览器和Web服务器之间交换，以根据您的Web应用程序需要跟踪各种信息。
Cookies are data, stored in small text files on your computer and it is exchanged between web browser and web server to keep track of various information based on your web application need.
您可以使用<meta>标记在客户端上存储cookie，此信息随后可由Web服务器用于跟踪网站访问者。
You can use <meta> tag to store cookies on client side and later this information can be used by the Web Server to track a site visitor.
Example
以下是将当前页面在 5 秒后重定向到另一页面的示例。如果希望立即重定向页面，那么不要指定 content 属性。
Following is an example of redirecting current page to another page after 5 seconds. If you want to redirect page immediately then do not specify content attribute.
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta http-equiv = "cookie" content = "userid = xyz; expires = Wednesday, 08-Aug-15 23:59:59 GMT;" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>如果您不包含到期日期和时间，则认为Cookie是一个会话Cookie，当用户退出浏览器时此Cookie将被删除。
If you do not include the expiration date and time, the cookie is considered a session cookie and will be deleted when the user exits the browser.
Note − 您可以查看 PHP and Cookies 教程以全面了解Cookie。
Note − You can check PHP and Cookies tutorial for a complete detail on Cookies.
Setting Author Name
您可以使用元标记在网页中设置作者姓名。请参阅以下示例：
You can set an author name in a web page using meta tag. See an example below −
Example
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "author" content = "Mahnaz Mohtashim" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>Specify Character Set
您可以使用<meta>标签来指定网页中使用的字符集。
You can use <meta> tag to specify character set used within the webpage.
Example
默认情况下，Web服务器和Web浏览器使用ISO-8859-1（Latin1）编码来处理Web页面。以下是设置UTF-8编码的示例：
By default, Web servers and Web browsers use ISO-8859-1 (Latin1) encoding to process Web pages. Following is an example to set UTF-8 encoding −
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "author" content = "Mahnaz Mohtashim" />
<meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>为了使用繁体中文提供静态页面，该网页必须包含一个<meta>标签来设置Big5编码：
To serve the static page with traditional Chinese characters, the webpage must contain a <meta> tag to set Big5 encoding −
<!DOCTYPE html>
<html>
<head>
<title>Meta Tags Example</title>
<meta name = "keywords" content = "HTML, Meta Tags, Metadata" />
<meta name = "description" content = "Learning about Meta Tags." />
<meta name = "author" content = "Mahnaz Mohtashim" />
<meta http-equiv = "Content-Type" content = "text/html; charset = Big5" />
</head>
<body>
<p>Hello HTML5!</p>
</body>
</html>HTML - Comments
注释是任何Web浏览器忽略的代码片段。在一个好的实践中，最好将注释添加到HTML代码中，尤其是在复杂文档中，以指示文档的部分和其他任何有关代码的说明。注释可以帮助您和其他人理解您的代码并提高代码的可读性。
Comment is a piece of code which is ignored by any web browser. It is a good practice to add comments into your HTML code, especially in complex documents, to indicate sections of a document, and any other notes to anyone looking at the code. Comments help you and others understand your code and increases code readability.
HTML注释放置在 <!-- … -→ 标签之间。因此，放在<!-- … -→标签之间的任何内容都将被视为注释，并且会被浏览器完全忽略。
HTML comments are placed in between <!-- … -→ tags. So, any content placed with-in <!-- … -→ tags will be treated as comment and will be completely ignored by the browser.
Example
<!DOCTYPE html>
<html>
<head> <!-- Document Header Starts -->
<title>This is document title</title>
</head> <!-- Document Header Ends -->
<body>
<p>Document content goes here.....</p>
</body>
</html>这将产生以下结果，不会显示作为注释一部分提供的内容：
This will produce the following result without displaying the content given as a part of comments −
Valid vs Invalid Comments
注释不能嵌套，这意味着不能将注释放入另一个注释中。其次，双破折号序列“--”不能出现在注释中，除非作为结束标记-→的一部分。您还必须确保注释字符串的开头没有空格。
Comments do not nest which means a comment cannot be put inside another comment. Second the double-dash sequence "--" may not appear inside a comment except as part of the closing -→ tag. You must also make sure that there are no spaces in the start-of comment string.
Example
在此，给定注释是一个有效注释，且将被浏览器抹去。
Here, the given comment is a valid comment and will be wiped off by the browser.
<!DOCTYPE html>
<html>
<head>
<title>Valid Comment Example</title>
</head>
<body>
<!-- This is valid comment -->
<p>Document content goes here.....</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
但是，以下行不是有效注释，且将被浏览器显示。这是因为左尖括号和感叹号之间有一个空格。
But, following line is not a valid comment and will be displayed by the browser. This is because there is a space between the left angle bracket and the exclamation mark.
<!DOCTYPE html>
<html>
<head>
<title>Invalid Comment Example</title>
</head>
<body>
< !-- This is not a valid comment -->
<p>Document content goes here.....</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Multiline Comments
到目前为止，我们已经看到单行注释，但 HTML 也支持多行注释。
So far we have seen single line comments, but HTML supports multi-line comments as well.
你可以通过放在第一行和最后一行结尾处的特殊开始标签 <!-- 和结束标签 -→ 来注释多行，如下面的给定示例所示。
You can comment multiple lines by the special beginning tag <!-- and ending tag -→ placed before the first line and end of the last line as shown in the given example below.
Conditional Comments
条件注释在 Windows 上只适用于 Internet Explorer (IE)，但它们被其他浏览器忽略。它们从 Explorer 5 开始受到支持，你可以使用它们向不同版本的 IE 提供条件说明。
Conditional comments only work in Internet Explorer (IE) on Windows but they are ignored by other browsers. They are supported from Explorer 5 onwards, and you can use them to give conditional instructions to different versions of IE.
Example
<!DOCTYPE html>
<html>
<head>
<title>Conditional Comments</title>
<!--[if IE 6]>
Special instructions for IE 6 here
<![endif]-->
</head>
<body>
<p>Document content goes here.....</p>
</body>
</html>你会遇到这样的情况：你需要根据不同版本的 Internet Explorer 应用不同的样式表，在这种情况下条件注释将很有帮助。
You will come across a situation where you will need to apply a different style sheet based on different versions of Internet Explorer, in such situation conditional comments will be helpful.
Using Comment Tag
支持 <comment> 标签来注释 HTML 代码一部分的浏览器很少。
There are few browsers that support <comment> tag to comment a part of HTML code.
Example
<!DOCTYPE html>
<html>
<head>
<title>Using Comment Tag</title>
</head>
<body>
<p>This is <comment>not</comment> Internet Explorer.</p>
</body>
</html>如果你使用 IE，那么它会产生以下结果 −
If you are using IE, then it will produce following result −
但如果你不使用 IE，那么它会产生以下结果 −
But if you are not using IE, then it will produce following result −
Commenting Script Code
尽管您将在单独的教程中同时学习 JavaScript 和 HTML，但您必须在此处注意，如果您在 HTML 代码中使用 Java Script 或 VB Script，则建议将该脚本代码放在适当的 HTML 注释内，以便旧浏览器能够正常运行。
Though you will learn JavaScript with HTML, in a separate tutorial, but here you must make a note that if you are using Java Script or VB Script in your HTML code then it is recommended to put that script code inside proper HTML comments so that old browsers can work properly.
Commenting Style Sheets
尽管您将在单独的教程中学习如何将样式表与 HTML 一起使用，但您必须在此处注意，如果您在 HTML 代码中使用级联样式表 (CSS)，则建议将该样式表代码放在适当的 HTML 注释内，以便旧浏览器能够正常运行。
Though you will learn using style sheets with HTML in a separate tutorial, but here you must make a note that if you are using Cascading Style Sheet (CSS) in your HTML code then it is recommended to put that style sheet code inside proper HTML comments so that old browsers can work properly.
HTML - Images
图片非常重要，不仅可以美化网页，还可以用简单的方式描绘许多复杂的概念。本教程将带您了解在网页中使用图片的简单步骤。
Images are very important to beautify as well as to depict many complex concepts in simple way on your web page. This tutorial will take you through simple steps to use images in your web pages.
Insert Image
您可以使用 <img> 标记在网页中插入任何图片。以下是使用该标记的简单语法。
You can insert any image in your web page by using <img> tag. Following is the simple syntax to use this tag.
<img src = "Image URL" ... attributes-list/><img> 标记是一个空标记，这意味着它只能包含属性列表，并且没有结束标记。
The <img> tag is an empty tag, which means that, it can contain only list of attributes and it has no closing tag.
Example
要尝试以下示例，让我们将 HTML 文件 test.htm 和图像文件 test.png 保存在同目录中 −
To try following example, let’s keep our HTML file test.htm and image file test.png in the same directory −
<!DOCTYPE html>
<html>
<head>
<title>Using Image in Webpage</title>
</head>
<body>
<p>Simple Image Insert</p>
<img src = "/html/images/test.png" alt = "Test Image" />
</body>
</html>这会产生以下结果 −
This will produce the following result −
您可以根据您的舒适度使用 PNG、JPEG 或 GIF 图像文件，但务必在 src 属性中指定正确的图像文件名。图像名称始终区分大小写。
You can use PNG, JPEG or GIF image file based on your comfort but make sure you specify correct image file name in src attribute. Image name is always case sensitive.
alt 属性是一个必需的属性，用于为图像指定替代文本（如果无法显示图像）。
The alt attribute is a mandatory attribute which specifies an alternate text for an image, if the image cannot be displayed.
Set Image Location
我们通常将所有图像保存在单独的目录中。因此，让我们将 HTML 文件 test.htm 保存在我们的主目录中，并在主目录内创建一个子目录 images ，我们将在其中保存我们的图像 test.png。
Usually we keep all the images in a separate directory. So let’s keep HTML file test.htm in our home directory and create a subdirectory images inside the home directory where we will keep our image test.png.
Example
假设我们的图像位置为“图像/test.png”，请尝试以下示例 −
Assuming our image location is "image/test.png", try the following example −
<!DOCTYPE html>
<html>
<head>
<title>Using Image in Webpage</title>
</head>
<body>
<p>Simple Image Insert</p>
<img src = "/html/images/test.png" alt = "Test Image" />
</body>
</html>这会产生以下结果 −
This will produce the following result −
Set Image Width/Height
您可以使用 width 和 height 属性根据您的要求设置图像宽度和高度。您可以指定图像的宽度和高度，以像素或实际大小的百分比表示。
You can set image width and height based on your requirement using width and height attributes. You can specify width and height of the image in terms of either pixels or percentage of its actual size.
Set Image Border
默认情况下，图像周围会有一个边框，您可以使用 border 属性指定边框粗细（以像素为单位）。粗细为 0 表示图片周围没有边框。
By default, image will have a border around it, you can specify border thickness in terms of pixels using border attribute. A thickness of 0 means, no border around the picture.
Set Image Alignment
默认情况下，图像将在页面的左侧对齐，但您可以使用 align 属性将其设置在中间或右侧。
By default, image will align at the left side of the page, but you can use align attribute to set it in the center or right.
Free Web Graphics
对于包括图案在内的免费网络图形，您可以查看 Free Web Graphics
For Free Web Graphics including patterns you can look into Free Web Graphics
HTML - Tables
HTML 表格允许网页作者将诸如文本、图像、链接、其他表格等数据排列成行和列。
The HTML tables allow web authors to arrange data like text, images, links, other tables, etc. into rows and columns of cells.
HTML 表格是使用 <table> 标记创建的，其中 <tr> 标记用于创建表格行， <td> 标记用于创建数据单元格。位于下的元素默认情况下是规则的和左对齐的
The HTML tables are created using the <table> tag in which the <tr> tag is used to create table rows and <td> tag is used to create data cells. The elements under <td> are regular and left aligned by default
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Tables</title>
</head>
<body>
<table border = "1">
<tr>
<td>Row 1, Column 1</td>
<td>Row 1, Column 2</td>
</tr>
<tr>
<td>Row 2, Column 1</td>
<td>Row 2, Column 2</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
这里， border 是 <table> 标记的一个属性，它用于在所有单元格上放置一个边框。如果您不需要边框，则可以使用 border = “0”。
Here, the border is an attribute of <table> tag and it is used to put a border across all the cells. If you do not need a border, then you can use border = "0".
Table Heading
可以使用 <th> 标记定义表格标题。该标记将替换 <td> 标记，该标记用于表示实际的数据单元格。通常，您会将顶行作为表格标题，如下所示，否则您可以在任何行中使用 <th> 元素。在 <th> 标记中定义的标题默认情况下是居中加粗的。
Table heading can be defined using <th> tag. This tag will be put to replace <td> tag, which is used to represent actual data cell. Normally you will put your top row as table heading as shown below, otherwise you can use <th> element in any row. Headings, which are defined in <th> tag are centered and bold by default.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Header</title>
</head>
<body>
<table border = "1">
<tr>
<th>Name</th>
<th>Salary</th>
</tr>
<tr>
<td>Ramesh Raman</td>
<td>5000</td>
</tr>
<tr>
<td>Shabbir Hussein</td>
<td>7000</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Cellpadding and Cellspacing Attributes
有两个属性 cellpadding 和 cellspacing，您将使用这两个属性调整表格单元格中的空白。cellspacing 属性定义表格单元格之间的空间，而 cellpadding 表示单元格边框和单元格内内容之间的距离。
There are two attributes called cellpadding and cellspacing which you will use to adjust the white space in your table cells. The cellspacing attribute defines space between table cells, while cellpadding represents the distance between cell borders and the content within a cell.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Cellpadding</title>
</head>
<body>
<table border = "1" cellpadding = "5" cellspacing = "5">
<tr>
<th>Name</th>
<th>Salary</th>
</tr>
<tr>
<td>Ramesh Raman</td>
<td>5000</td>
</tr>
<tr>
<td>Shabbir Hussein</td>
<td>7000</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Colspan and Rowspan Attributes
如果您想将两个或更多列合并成一列，您将使用 colspan 属性。您想合并两行或更多行，您可以使用 rowspan 。
You will use colspan attribute if you want to merge two or more columns into a single column. Similar way you will use rowspan if you want to merge two or more rows.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Colspan/Rowspan</title>
</head>
<body>
<table border = "1">
<tr>
<th>Column 1</th>
<th>Column 2</th>
<th>Column 3</th>
</tr>
<tr>
<td rowspan = "2">Row 1 Cell 1</td>
<td>Row 1 Cell 2</td>
<td>Row 1 Cell 3</td>
</tr>
<tr>
<td>Row 2 Cell 2</td>
<td>Row 2 Cell 3</td>
</tr>
<tr>
<td colspan = "3">Row 3 Cell 1</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Tables Backgrounds
您可以使用以下两种方法之一设置表格背景 -
You can set table background using one of the following two ways −
-
bgcolor attribute − You can set background color for whole table or just for one cell.
-
background attribute − You can set background image for whole table or just for one cell.
您还可以使用 bordercolor 属性设置边框颜色。
You can also set border color also using bordercolor attribute.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Background</title>
</head>
<body>
<table border = "1" bordercolor = "green" bgcolor = "yellow">
<tr>
<th>Column 1</th>
<th>Column 2</th>
<th>Column 3</th>
</tr>
<tr>
<td rowspan = "2">Row 1 Cell 1</td>
<td>Row 1 Cell 2</td>
<td>Row 1 Cell 3</td>
</tr>
<tr>
<td>Row 2 Cell 2</td>
<td>Row 2 Cell 3</td>
</tr>
<tr>
<td colspan = "3">Row 3 Cell 1</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
以下是如何使用 background 属性的示例。这里我们使用 /images 目录中可用的图像。
Here is an example of using background attribute. Here we will use an image available in /images directory.
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Background</title>
</head>
<body>
<table border = "1" bordercolor = "green" background = "/images/test.png">
<tr>
<th>Column 1</th>
<th>Column 2</th>
<th>Column 3</th>
</tr>
<tr>
<td rowspan = "2">Row 1 Cell 1</td>
<td>Row 1 Cell 2</td><td>Row 1 Cell 3</td>
</tr>
<tr>
<td>Row 2 Cell 2</td>
<td>Row 2 Cell 3</td>
</tr>
<tr>
<td colspan = "3">Row 3 Cell 1</td>
</tr>
</table>
</body>
</html>这会产生以下结果。这里的背景图像不适合应用到表格的标题。
This will produce the following result. Here background image did not apply to table’s header.
Table Height and Width
您可以使用 width 和 height 属性设置表格的宽度和高度。您可以以像素或可用屏幕区域的百分比来指定表格的宽度或高度。
You can set a table width and height using width and height attributes. You can specify table width or height in terms of pixels or in terms of percentage of available screen area.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Width/Height</title>
</head>
<body>
<table border = "1" width = "400" height = "150">
<tr>
<td>Row 1, Column 1</td>
<td>Row 1, Column 2</td>
</tr>
<tr>
<td>Row 2, Column 1</td>
<td>Row 2, Column 2</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Table Caption
caption 标记将用作表格的标题或说明，并且它显示在表格的顶部。此标记在较新版本的 HTML/XHTML 中已弃用。
The caption tag will serve as a title or explanation for the table and it shows up at the top of the table. This tag is deprecated in newer version of HTML/XHTML.
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table Caption</title>
</head>
<body>
<table border = "1" width = "100%">
<caption>This is the caption</caption>
<tr>
<td>row 1, column 1</td><td>row 1, columnn 2</td>
</tr>
<tr>
<td>row 2, column 1</td><td>row 2, columnn 2</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Table Header, Body, and Footer
表格可以分为三个部分 - 头部、主体和页脚。头部和页脚有点类似于文字处理文档中的页眉和页脚，它们对于每一页都保持不变，而主体则是表格的主要内容持有者。
Tables can be divided into three portions − a header, a body, and a foot. The head and foot are rather similar to headers and footers in a word-processed document that remain the same for every page, while the body is the main content holder of the table.
用于分隔表格头部、正文和脚部的三个元素是 −
The three elements for separating the head, body, and foot of a table are −
-
<thead> − to create a separate table header.
-
<tbody> − to indicate the main body of the table.
-
<tfoot> − to create a separate table footer.
一个表格可以包含多个 <tbody> 元素来表示不同的页面或数据组。但值得注意的是，<thead> 和 <tfoot> 标记应该出现在 <tbody> 之前。
A table may contain several <tbody> elements to indicate different pages or groups of data. But it is notable that <thead> and <tfoot> tags should appear before <tbody>
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Table</title>
</head>
<body>
<table border = "1" width = "100%">
<thead>
<tr>
<td colspan = "4">This is the head of the table</td>
</tr>
</thead>
<tfoot>
<tr>
<td colspan = "4">This is the foot of the table</td>
</tr>
</tfoot>
<tbody>
<tr>
<td>Cell 1</td>
<td>Cell 2</td>
<td>Cell 3</td>
<td>Cell 4</td>
</tr>
</tbody>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Nested Tables
您可以在另一个表格内使用一个表格。您不仅可以在表格内使用表格，几乎可以使用所有标记。
You can use one table inside another table. Not only tables you can use almost all the tags inside table data tag <td>.
Example
下面是在表格单元格内使用另一个表格和其他标记的示例。
Following is the example of using another table and other tags inside a table cell.
<!DOCTYPE html>
<html>
<head>
<title>HTML Table</title>
</head>
<body>
<table border = "1" width = "100%">
<tr>
<td>
<table border = "1" width = "100%">
<tr>
<th>Name</th>
<th>Salary</th>
</tr>
<tr>
<td>Ramesh Raman</td>
<td>5000</td>
</tr>
<tr>
<td>Shabbir Hussein</td>
<td>7000</td>
</tr>
</table>
</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Lists
HTML 为 Web 作者提供了三种指定信息列表的方法。所有列表都必须包含一个或多个列表元素。列表可能包含 -
HTML offers web authors three ways for specifying lists of information. All lists must contain one or more list elements. Lists may contain −
-
<ul> − An unordered list. This will list items using plain bullets.
-
<ol> − An ordered list. This will use different schemes of numbers to list your items.
-
<dl> − A definition list. This arranges your items in the same way as they are arranged in a dictionary.
HTML Unordered Lists
无序列表是相关项的集合，没有特定顺序或序列。此列表使用 HTML <ul> 标记创建。列表中的每个项目都用项目符号标记。
An unordered list is a collection of related items that have no special order or sequence. This list is created by using HTML <ul> tag. Each item in the list is marked with a bullet.
The type Attribute
您可以使用 <ul> 标记的 type 属性指定要使用的项目符号类型。默认情况下，它是一个圆盘。以下是可能选项 −
You can use type attribute for <ul> tag to specify the type of bullet you like. By default, it is a disc. Following are the possible options −
<ul type = "square">
<ul type = "disc">
<ul type = "circle">Example
以下是我们使用 <ul type = "square"> 的示例
Following is an example where we used <ul type = "square">
<!DOCTYPE html>
<html>
<head>
<title>HTML Unordered List</title>
</head>
<body>
<ul type = "square">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ul>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ul type = "disc"> 的示例 −
Following is an example where we used <ul type = "disc"> −
<!DOCTYPE html>
<html>
<head>
<title>HTML Unordered List</title>
</head>
<body>
<ul type = "disc">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ul>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ul type = "circle"> 的示例 −
Following is an example where we used <ul type = "circle"> −
<!DOCTYPE html>
<html>
<head>
<title>HTML Unordered List</title>
</head>
<body>
<ul type = "circle">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ul>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML Ordered Lists
如果您需要将项目放入编号列表而不是项目符号列表中，则将使用 HTML 有序列表。此列表使用 <ol> 标记创建。编号从 1 开始，并为标记有 <li> 的每个连续有序列表元素递增 1。
If you are required to put your items in a numbered list instead of bulleted, then HTML ordered list will be used. This list is created by using <ol> tag. The numbering starts at one and is incremented by one for each successive ordered list element tagged with <li>.
The type Attribute
您可以使用 <ol> 标记的 type 属性指定要使用的编号类型。默认情况下，它是一个数字。以下是可能选项 −
You can use type attribute for <ol> tag to specify the type of numbering you like. By default, it is a number. Following are the possible options −
<ol type = "1"> - Default-Case Numerals.
<ol type = "I"> - Upper-Case Numerals.
<ol type = "i"> - Lower-Case Numerals.
<ol type = "A"> - Upper-Case Letters.
<ol type = "a"> - Lower-Case Letters.Example
以下是我们使用 <ol type = "1"> 的示例
Following is an example where we used <ol type = "1">
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "1">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ol type = "I"> 的示例
Following is an example where we used <ol type = "I">
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "I">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ol type = "i"> 的示例
Following is an example where we used <ol type = "i">
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "i">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ol type = "A" > 的示例
Following is an example where we used <ol type = "A" >
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "A">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Example
以下是我们使用 <ol type = "a"> 的示例
Following is an example where we used <ol type = "a">
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "a">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The start Attribute
您可以使用 <ol> 标记的 start 属性指定您需要的编号的起始点。以下是可能选项 −
You can use start attribute for <ol> tag to specify the starting point of numbering you need. Following are the possible options −
<ol type = "1" start = "4"> - Numerals starts with 4.
<ol type = "I" start = "4"> - Numerals starts with IV.
<ol type = "i" start = "4"> - Numerals starts with iv.
<ol type = "a" start = "4"> - Letters starts with d.
<ol type = "A" start = "4"> - Letters starts with D.Example
以下是我们使用 <ol type = "i" start = "4" > 的示例
Following is an example where we used <ol type = "i" start = "4" >
<!DOCTYPE html>
<html>
<head>
<title>HTML Ordered List</title>
</head>
<body>
<ol type = "i" start = "4">
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ol>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML Definition Lists
HTML 和 XHTML 支持称为 definition lists 的列表样式，其中项目像字典或百科全书一样列出。定义列表是展示词汇表、术语列表或其他名称/值列表的理想方式。
HTML and XHTML supports a list style which is called definition lists where entries are listed like in a dictionary or encyclopedia. The definition list is the ideal way to present a glossary, list of terms, or other name/value list.
定义列表使用以下三个标记。
Definition List makes use of following three tags.
-
<dl> − Defines the start of the list
-
<dt> − A term
-
<dd> − Term definition
-
</dl> − Defines the end of the list
Example
<!DOCTYPE html>
<html>
<head>
<title>HTML Definition List</title>
</head>
<body>
<dl>
<dt><b>HTML</b></dt>
<dd>This stands for Hyper Text Markup Language</dd>
<dt><b>HTTP</b></dt>
<dd>This stands for Hyper Text Transfer Protocol</dd>
</dl>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Text Links
一个网页可以包含各种链接，这些链接可以将您直接带到其他页面，甚至特定页面的特定部分。这些链接称为超链接。
A webpage can contain various links that take you directly to other pages and even specific parts of a given page. These links are known as hyperlinks.
超链接允许访客通过点击单词、短语和图像在网站之间导航。因此，您可以使用网页中可用的文本或图像创建超链接。
Hyperlinks allow visitors to navigate between Web sites by clicking on words, phrases, and images. Thus you can create hyperlinks using text or images available on a webpage.
Note − 我建议你阅读 Understanding URL 上的一个简短教程
Note − I recommend you to go through a short tutorial on Understanding URL
Linking Documents
使用 HTML 标记 <a> 指定链接。此标记称为 anchor tag 介于开始标记 <a> 和结束标记 </a> 之间的所有内容，均成为链接的一部分，用户可以点击该部分到达链接的文档。以下是使用 <a> 标记的简单语法。
A link is specified using HTML tag <a>. This tag is called anchor tag and anything between the opening <a> tag and the closing </a> tag becomes part of the link and a user can click that part to reach to the linked document. Following is the simple syntax to use <a> tag.
<a href = "Document URL" ... attributes-list>Link Text</a>Example
让我们尝试以下示例，该示例链接 [role="bare"] [role="bare"]https://www.tutorialspoint.com 在你的页面上 −
Let’s try following example which links [role="bare"]https://www.tutorialspoint.com at your page −
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
</head>
<body>
<p>Click following link</p>
<a href = "https://www.tutorialspoint.com" target = "_self">Tutorials Point</a>
</body>
</html>这将产生以下结果，您可以在其中单击生成的链接以访问 Tutorials Point 的主页（在此示例中）。
This will produce the following result, where you can click on the link generated to reach to the home page of Tutorials Point (in this example).
The target Attribute
我们在前面的示例中使用了 target 属性。此属性用于指定链接的文档打开的位置。以下是可以行的选项 −
We have used target attribute in our previous example. This attribute is used to specify the location where linked document is opened. Following are the possible options −
Sr.No |
Option & Description |
1 |
_blank Opens the linked document in a new window or tab. |
2 |
_self Opens the linked document in the same frame. |
3 |
_parent Opens the linked document in the parent frame. |
4 |
_top Opens the linked document in the full body of the window. |
5 |
targetframe Opens the linked document in a named targetframe. |
Example
尝试以下示例，了解为目标属性给出的一些选项中的基本差异。
Try following example to understand basic difference in few options given for target attribute.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<base href = "https://www.tutorialspoint.com/">
</head>
<body>
<p>Click any of the following links</p>
<a href = "/html/index.htm" target = "_blank">Opens in New</a> |
<a href = "/html/index.htm" target = "_self">Opens in Self</a> |
<a href = "/html/index.htm" target = "_parent">Opens in Parent</a> |
<a href = "/html/index.htm" target = "_top">Opens in Body</a>
</body>
</html>这将产生以下结果，您可以在其中单击不同的链接来了解为目标属性给出的不同选项之间的差异。
This will produce the following result, where you can click on different links to understand the difference between various options given for target attribute.
Use of Base Path
当你链接到同一网站相关的 HTML 文档时，没有必要为每个链接提供一个完整的 URL。如果你在你 HTML 文档头中使用 <base> 标签，你便可以不用提供完整 URL。该标签用于为所有链接提供一个基本路径。这样你的浏览器会将给定的相对路径与其基本路径连接，并将形成一个完整的 URL。
When you link HTML documents related to the same website, it is not required to give a complete URL for every link. You can get rid of it if you use <base> tag in your HTML document header. This tag is used to give a base path for all the links. So your browser will concatenate given relative path to this base path and will make a complete URL.
Example
以下示例使用 <base> 标记指定基本 URL，稍后我们可以使用相对路径链接到所有链接，而无需为每个链接提供完整 URL。
Following example makes use of <base> tag to specify base URL and later we can use relative path to all the links instead of giving complete URL for every link.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<base href = "https://www.tutorialspoint.com/">
</head>
<body>
<p>Click following link</p>
<a href = "/html/index.htm" target = "_blank">HTML Tutorial</a>
</body>
</html>这将产生以下结果，您可以在其中单击生成的链接 HTML Tutorial 访问 HTML 教程。
This will produce the following result, where you can click on the link generated HTML Tutorial to reach to the HTML tutorial.
现在给定的 URL <a href = "/html/index.htm" 被视为 <ahref = "https://www.tutorialspoint.com/html/index.htm"
Now given URL <a href = "/html/index.htm" is being considered as <ahref = "https://www.tutorialspoint.com/html/index.htm"
Linking to a Page Section
您可以使用 name 属性创建到给定网页特定部分的链接。这是一个两步过程。
You can create a link to a particular section of a given webpage by using name attribute. This is a two-step process.
首先，创建一个链接到你要在网页中到达的地方，并使用 <a…> 标记将其命名如下 −
First create a link to the place where you want to reach with-in a webpage and name it using <a…> tag as follows −
<h1>HTML Text Links <a name = "top"></a></h1>第二步是创建一个超链接来链接该文档和你要到达的地方 −
Second step is to create a hyperlink to link the document and place where you want to reach −
<a href = "/html/html_text_links.htm#top">Go to the Top</a>这将生成以下链接，您可以在该链接中点击生成链接 Go to the Top 以到达 HTML 文本链接教程的顶部。
This will produce following link, where you can click on the link generated Go to the Top to reach to the top of the HTML Text Link tutorial.
Go to the TopSetting Link Colors
您可以使用 link 、 alink 和 vlink 属性 <body> 标记来设置链接、活动链接和已访问链接的颜色。
You can set colors of your links, active links and visited links using link, alink and vlink attributes of <body> tag.
Example
将以下内容保存到 test.htm 中并在任何网络浏览器中打开它，以便查看 link 、 alink 和 vlink 属性如何工作。
Save the following in test.htm and open it in any web browser to see how link, alink and vlink attributes work.
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
<base href = "https://www.tutorialspoint.com/">
</head>
<body alink = "#54A250" link = "#040404" vlink = "#F40633">
<p>Click following link</p>
<a href = "/html/index.htm" target = "_blank" >HTML Tutorial</a>
</body>
</html>这将生成以下结果。只需在点击链接之前检查其颜色，然后在激活链接时和在已访问链接时检查其颜色即可。
This will produce the following result. Just check color of the link before clicking on it, next check its color when you activate it and when the link has been visited.
Download Links
您可以创建文本链接，让您的 PDF、DOC 或 ZIP 文件可下载。这一操作非常简单；您只需指定可下载文件的完整 URL，如下所示：
You can create text link to make your PDF, or DOC or ZIP files downloadable. This is very simple; you just need to give complete URL of the downloadable file as follows −
<!DOCTYPE html>
<html>
<head>
<title>Hyperlink Example</title>
</head>
<body>
<a href = "https://www.tutorialspoint.com/page.pdf">Download PDF File</a>
</body>
</html>这将生成以下链接并将用于下载文件。
This will produce following link and will be used to download a file.
File Download Dialog Box
有时您希望提供一个选项，即用户单击一个链接并会弹出“文件下载”框，而不是显示实际内容。这一操作非常容易，可以使用 HTTP 响应中的 HTTP 标头来实现。
Sometimes it is desired that you want to give an option where a user will click a link and it will pop up a "File Download" box to the user instead of displaying actual content. This is very easy and can be achieved using an HTTP header in your HTTP response.
例如，如果您希望使 Filename 文件可从给定链接下载，则其语法如下。
For example, if you want make a Filename file downloadable from a given link then its syntax will be as follows.
#!/usr/bin/perl
# Additional HTTP Header
print "Content-Type:application/octet-stream; name = \"FileName\"\r\n";
print "Content-Disposition:attachment; filename = \"FileName\"\r\n\n";
# Open the target file and list down its content as follows
open( FILE, "<FileName" );
while(read(FILE, $buffer, 100)){
print("$buffer");
}Note - 有关 PERL CGI 程序的更详细信息，请仔细阅读教程 PERL and CGI 。
Note − For more detail on PERL CGI programs, go through tutorial PERL and CGI.
HTML - Image Links
我们已经了解到使用文本创建超文本链接，还学习了如何在我们的网页中使用图片。现在，我们将学习如何使用图片创建超链接。
We have seen how to create hypertext link using text and we also learnt how to use images in our webpages. Now, we will learn how to use images to create hyperlinks.
Example
使用图像作为超链接非常简单。我们只需使用超链接内的图像，以取代文本，如下所示 −
It’s simple to use an image as hyperlink. We just need to use an image inside hyperlink at the place of text as shown below −
<!DOCTYPE html>
<html>
<head>
<title>Image Hyperlink Example</title>
</head>
<body>
<p>Click following link</p>
<a href = "https://www.tutorialspoint.com" target = "_self">
<img src = "/images/logo.png" alt = "Tutorials Point" border = "0"/>
</a>
</body>
</html>这会生成以下结果，您可以单击这些图像来访问 Tutorials Point 的主页。
This will produce the following result, where you can click on the images to reach to the home page of Tutorials Point.
这是使用图像创建超链接的最简单方法。接下来，我们将看到如何创建鼠标敏感图像链接。
This was the simplest way of creating hyperlinks using images. Next we will see how we can create Mouse-Sensitive Image Links.
Mouse-Sensitive Images
HTML 和 XHTML 标准提供了一个功能，它允许您在单个图像中嵌入许多不同的链接。您可以根据图像上可用的不同坐标在单个图像上创建不同的链接。一旦将不同的链接附加到不同的坐标，我们就可以单击图像的不同部分来打开目标文档。这种鼠标敏感图像被称为图像映射。
The HTML and XHTML standards provides a feature that lets you embed many different links inside a single image. You can create different links on the single image based on different coordinates available on the image. Once different links are attached to different coordinates, we can click different parts of the image to open target documents. Such mouse-sensitive images are known as image maps.
有两种创建图像映射的方法 −
There are two ways to create image maps −
-
Server-side image maps − This is enabled by the ismap attribute of the <img> tag and requires access to a server and related image-map processing applications.
-
Client-side image maps − This is created with the usemap attribute of the <img> tag, along with corresponding <map> and <area> tags.
Server-Side Image Maps
这里，您只需将图像放入超链接内，并使用将其变为特殊图像的 ismap 属性，当用户单击图像内的某个位置时，浏览器会将鼠标指针的坐标以及 <a> 标记中指定的 URL 传递给网络服务器。服务器使用鼠标指针坐标来确定要传送到浏览器的文档。
Here you simply put your image inside a hyper link and use ismap attribute which makes it special image and when the user clicks some place within the image, the browser passes the coordinates of the mouse pointer along with the URL specified in the <a> tag to the web server. The server uses the mouse-pointer coordinates to determine which document to deliver back to the browser.
当使用 ismap 时，包含 <a> 标记的 href 属性必须包含服务器应用程序的 URL，例如 cgi 或 PHP 脚本等，以根据传递的坐标来处理传入的请求。
When ismap is used, the href attribute of the containing <a> tag must contain the URL of a server application like a cgi or PHP script etc. to process the incoming request based on the passed coordinates.
鼠标位置的坐标是屏幕像素，从图像的左上角开始计数，从 (0,0) 开始。坐标在问号之前，被添加到 URL 的末尾。
The coordinates of the mouse position are screen pixels counted from the upper-left corner of the image, beginning with (0,0). The coordinates, preceded by a question mark, are added to the end of the URL.
例如，如果用户点击了以下图像左上角 20 像素宽和 30 像素高的区域 −
For example, if a user clicks 20 pixels over and 30 pixels down from the upper-left corner of the following image −
这是由以下代码段生成的 −
Which has been generated by the following code snippet −
<!DOCTYPE html>
<html>
<head>
<title>ISMAP Hyperlink Example</title>
</head>
<body>
<p>Click following link</p>
<a href = "/cgi-bin/ismap.cgi" target = "_self">
<img ismap src = "/images/logo.png" alt = "Tutorials Point" border = "0"/>
</a>
</body>
</html>然后，浏览器会将以下搜索参数发送到网络服务器，这些参数可以由 ismap.cgi 脚本或 map file 处理，您可以将您喜欢的任何文档链接到这些坐标 −
Then the browser sends the following search parameters to the web server which can be processed by ismap.cgi script or map file and you can link whatever documents you like to these coordinates −
/cgi-bin/ismap.cgi?20,30这样，您可以为图像的不同坐标分配不同的链接，当单击这些坐标时，您可以打开相应的链接文档。要了解有关 ismap 属性的更多信息，您可以查看 How to use Image ismap?
This way you can assign different links to different coordinates of the image and when those coordinates are clicked, you can open corresponding linked document. To learn more about ismap attribute, you can check How to use Image ismap?
Client-Side Image Maps
客户端图像映射是通过 <img /> 标记的 usemap 属性启用的，并通过特殊的 <map> 和 <area> 扩展标记定义的。
Client side image maps are enabled by the usemap attribute of the <img /> tag and defined by special <map> and <area> extension tags.
组成映射的图像使用 <img /> 标记作为普通图像插入到页面中，除了它带有一个称为 usemap 的额外属性。usemap 属性的值是将用于 <map> 标记的值，以将 map 和 image 标记链接起来。带有 <area> 标记的 <map> 定义了所有图像坐标和相应的链接。
The image that is going to form the map is inserted into the page using the <img /> tag as a normal image, except it carries an extra attribute called usemap. The value of the usemap attribute is the value which will be used in a <map> tag to link map and image tags. The <map> along with <area> tags define all the image coordinates and corresponding links.
map 标记内的 <area> 标记指定形状和坐标以定义图像上可用的每个可点击热点区域的边界。下面是图像映射的示例 −
The <area> tag inside the map tag, specifies the shape and the coordinates to define the boundaries of each clickable hotspot available on the image. Here’s an example from the image map −
<!DOCTYPE html>
<html>
<head>
<title>USEMAP Hyperlink Example</title>
</head>
<body>
<p>Search and click the hotspot</p>
<img src = /images/html.gif alt = "HTML Map" border = "0" usemap = "#html"/>
<!-- Create Mappings -->
<map name = "html">
<area shape = "circle" coords = "80,80,20"
href = "/css/index.htm" alt = "CSS Link" target = "_self" />
<area shape = "rect" coords = "5,5,40,40" alt = "jQuery Link"
href = "/jquery/index.htm" target = "_self" />
</map>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Coordinate System
coords 的实际值完全取决于有问题的形状。这里有一个摘要，后面是详细示例 −
The actual value of coords is totally dependent on the shape in question. Here is a summary, to be followed by detailed examples −
-
rect = x1 , y1 , x2 , y2 x1 and y1 are the coordinates of the upper left corner of the rectangle; x2 and y2 are the coordinates of the lower right corner.
-
circle = xc , yc , radius xc and yc are the coordinates of the center of the circle, and radius is the circle’s radius. A circle centered at 200,50 with a radius of 25 would have the attribute coords = "200,50,25"
-
poly = x1 , y1 , x2 , y2 , x3 , y3 , … xn , yn The various x-y pairs define vertices (points) of the polygon, with a "line" being drawn from one point to the next point. A diamond-shaped polygon with its top point at 20,20 and 40 pixels across at its widest points would have the attribute coords = "20,20,40,40,20,60,0,40".
所有坐标都相对于图片的左上角（0,0）。每个形状都具有一个相关的 URL。您可以使用任何图片软件来了解不同位置的坐标。
All coordinates are relative to the upper-left corner of the image (0,0). Each shape has a related URL. You can use any image software to know the coordinates of different positions.
HTML - Email Links
在您的网页上放置一个 HTML 电子邮件链接很容易，但它可能会给您的电子邮件帐户造成不必要的垃圾邮件问题。有人可以运行程序来收集这些类型的电子邮件，然后用各种方式使用它们发送垃圾邮件。
It is not difficult to put an HTML email link on your webpage but it can cause unnecessary spamming problem for your email account. There are people, who can run programs to harvest these types of emails and later use them for spamming in various ways.
您还可以提供其他选项，方便人们给您发送电子邮件。一个选项是使用 HTML 表单收集用户数据，然后使用 PHP 或 CGI 脚本发送电子邮件。
You can have another option to facilitate people to send you emails. One option could be to use HTML forms to collect user data and then use PHP or CGI script to send an email.
一个简单的示例，请查看我们的 Contact Us 表单。我们使用此表单收集用户反馈，然后我们正在使用一个正在收集此信息并将电子邮件发送到一个给定的电子邮件 ID 的 CGI 程序。
A simple example, check our Contact Us Form. We take user feedback using this form and then we are using one CGI program which is collecting this information and sending us email to the one given email ID.
Note - 您将在 HTML Forms 中了解 HTML 表单，您将在我们的另一个教程 Perl CGI Programming 中了解 CGI。
Note − You will learn about HTML Forms in HTML Forms and you will learn about CGI in our another tutorial Perl CGI Programming.
HTML Email Tag
HTML <a> 标记为您提供指定电子邮件地址以发送电子邮件的选项。在使用 <a> 标记作为电子邮件标记时，您将使用 mailto: email address 以及 href 属性。以下是使用 mailto 而不是使用 http 的语法。
HTML <a> tag provides you option to specify an email address to send an email. While using <a> tag as an email tag, you will use mailto: email address along with href attribute. Following is the syntax of using mailto instead of using http.
<a href = "mailto: abc@example.com">Send Email</a>此代码将生成以下链接，您可以使用该链接发送电子邮件。
This code will generate the following link which you can use to send email.
Send Email现在，如果用户单击此链接，它将启动安装在用户电脑上的一个电子邮件客户端（例如 Lotus Notes、Outlook Express 等）。使用此选项发送电子邮件有另一个风险，因为如果用户的电脑上未安装电子邮件客户端，则无法发送电子邮件。
Now, if a user clicks this link, it launches one Email Client (like Lotus Notes, Outlook Express etc. ) installed on your user’s computer. There is another risk to use this option to send email because if user do not have email client installed on their computer then it would not be possible to send email.
Default Settings
您可以指定默认电子邮件主题和电子邮件正文以及您的电子邮件地址。以下是使用默认主题和正文的示例。
You can specify a default email subject and email body along with your email address. Following is the example to use default subject and body.
<a href = "mailto:abc@example.com?subject = Feedback&body = Message">
Send Feedback
</a>此代码将生成以下链接，您可以使用该链接发送电子邮件。
This code will generate the following link which you can use to send email.
Send FeedbackHTML - Frames
HTML 框架用于将您的浏览器窗口划分为多个部分，其中每个部分都可以加载一个单独的 HTML 文档。浏览器窗口中的框架集合称为框架集。窗口被划分为框架的方式类似于表格的组织方式：分为行和列。
HTML frames are used to divide your browser window into multiple sections where each section can load a separate HTML document. A collection of frames in the browser window is known as a frameset. The window is divided into frames in a similar way the tables are organized: into rows and columns.
Disadvantages of Frames
使用框架有一些缺点，因此不建议在您的网页中使用框架 −
There are few drawbacks with using frames, so it’s never recommended to use frames in your webpages −
-
Some smaller devices cannot cope with frames often because their screen is not big enough to be divided up.
-
Sometimes your page will be displayed differently on different computers due to different screen resolution.
-
The browser’s back button might not work as the user hopes.
-
There are still few browsers that do not support frame technology.
Creating Frames
要在页面上使用框架，我们使用 <frameset> 标签而不是 <body> 标签。 <frameset> 标签定义了如何将窗口划分为框架。 <frameset> 标签的 rows 属性定义水平框架， cols 属性定义垂直框架。每个框架都由 <frame> 标签表示，它定义了哪个 HTML 文档将在框架中打开。
To use frames on a page we use <frameset> tag instead of <body> tag. The <frameset> tag defines, how to divide the window into frames. The rows attribute of <frameset> tag defines horizontal frames and cols attribute defines vertical frames. Each frame is indicated by <frame> tag and it defines which HTML document shall open into the frame.
Example
以下是创建三个水平框架的示例 −
Following is the example to create three horizontal frames −
<!DOCTYPE html>
<html>
<head>
<title>HTML Frames</title>
</head>
<frameset rows = "10%,80%,10%">
<frame name = "top" src = "/html/top_frame.htm" />
<frame name = "main" src = "/html/main_frame.htm" />
<frame name = "bottom" src = "/html/bottom_frame.htm" />
<noframes>
<body>Your browser does not support frames.</body>
</noframes>
</frameset>
</html>这会产生以下结果 −
This will produce the following result −
Example
让我们按以下所示放置上述示例，在此处我们用 cols 替换 rows 属性并更改它们的宽度。这将垂直创建所有三个框架 −
Let’s put the above example as follows, here we replaced rows attribute by cols and changed their width. This will create all the three frames vertically −
<!DOCTYPE html>
<html>
<head>
<title>HTML Frames</title>
</head>
<frameset cols = "25%,50%,25%">
<frame name = "left" src = "/html/top_frame.htm" />
<frame name = "center" src = "/html/main_frame.htm" />
<frame name = "right" src = "/html/bottom_frame.htm" />
<noframes>
<body>Your browser does not support frames.</body>
</noframes>
</frameset>
</html>这会产生以下结果 −
This will produce the following result −
The <frameset> Tag Attributes
以下是 <frameset> 标签的重要属性−
Following are important attributes of the <frameset> tag −
Sr.No |
Attribute & Description |
1 |
cols Specifies how many columns are contained in the frameset and the size of each column. You can specify the width of each column in one of the four ways − Absolute values in pixels. For example, to create three vertical frames, use cols = "100, 500, 100". A percentage of the browser window. For example, to create three vertical frames, use cols = "10%, 80%, 10%". Using a wildcard symbol. For example, to create three vertical frames, use cols = "10%, , 10%". In this case wildcard takes remainder of the window. As relative widths of the browser window. For example, to create three vertical frames, use cols = "3, 2*, 1*". This is an alternative to percentages. You can use relative widths of the browser window. Here the window is divided into sixths: the first column takes up half of the window, the second takes one third, and the third takes one sixth. |
2 |
rows This attribute works just like the cols attribute and takes the same values, but it is used to specify the rows in the frameset. For example, to create two horizontal frames, use rows = "10%, 90%". You can specify the height of each row in the same way as explained above for columns. |
3 |
border This attribute specifies the width of the border of each frame in pixels. For example, border = "5". A value of zero means no border. |
4 |
frameborder This attribute specifies whether a three-dimensional border should be displayed between frames. This attribute takes value either 1 (yes) or 0 (no). For example frameborder = "0" specifies no border. |
5 |
framespacing This attribute specifies the amount of space between frames in a frameset. This can take any integer value. For example framespacing = "10" means there should be 10 pixels spacing between each frames. |
The <frame> Tag Attributes
以下是 <frame> 标签的重要属性 −
Following are the important attributes of <frame> tag −
Sr.No |
Attribute & Description |
1 |
src This attribute is used to give the file name that should be loaded in the frame. Its value can be any URL. For example, src = "/html/top_frame.htm" will load an HTML file available in html directory. |
2 |
name This attribute allows you to give a name to a frame. It is used to indicate which frame a document should be loaded into. This is especially important when you want to create links in one frame that load pages into an another frame, in which case the second frame needs a name to identify itself as the target of the link. |
3 |
frameborder This attribute specifies whether or not the borders of that frame are shown; it overrides the value given in the frameborder attribute on the <frameset> tag if one is given, and this can take values either 1 (yes) or 0 (no). |
4 |
marginwidth This attribute allows you to specify the width of the space between the left and right of the frame’s borders and the frame’s content. The value is given in pixels. For example marginwidth = "10". |
5 |
marginheight This attribute allows you to specify the height of the space between the top and bottom of the frame’s borders and its contents. The value is given in pixels. For example marginheight = "10". |
6 |
noresize By default, you can resize any frame by clicking and dragging on the borders of a frame. The noresize attribute prevents a user from being able to resize the frame. For example noresize = "noresize". |
7 |
scrolling This attribute controls the appearance of the scrollbars that appear on the frame. This takes values either "yes", "no" or "auto". For example scrolling = "no" means it should not have scroll bars. |
8 |
longdesc This attribute allows you to provide a link to another page containing a long description of the contents of the frame. For example longdesc = "framedescription.htm" |
Browser Support for Frames
如果用户使用的是任何旧浏览器或不支持帧的任何浏览器，则应向用户显示 <noframes> 元素。
If a user is using any old browser or any browser, which does not support frames then <noframes> element should be displayed to the user.
因此，你必须在 <noframes> 元素中放置一个 <body> 元素，因为 <frameset> 元素应该替换 <body> 元素，但是如果浏览器不理解 <frameset> 元素，则它应该理解 <noframes> 元素中包含的 <body> 元素的内容。
So you must place a <body> element inside the <noframes> element because the <frameset> element is supposed to replace the <body> element, but if a browser does not understand <frameset> element then it should understand what is inside the <body> element which is contained in a <noframes> element.
你可以为使用旧浏览器的用户放置一些好的消息。例如，抱歉！！你的浏览器不支持框架。如上例所示。
You can put some nice message for your user having old browsers. For example, Sorry!! your browser does not support frames. as shown in the above example.
Frame’s name and target attributes
帧最流行的用途之一是在一个帧中放置导航栏，然后将主页加载到一个单独的帧中。
One of the most popular uses of frames is to place navigation bars in one frame and then load main pages into a separate frame.
让我们看以下示例，其中 test.htm 文件具有以下代码 −
Let’s see following example where a test.htm file has following code −
<!DOCTYPE html>
<html>
<head>
<title>HTML Target Frames</title>
</head>
<frameset cols = "200, *">
<frame src = "/html/menu.htm" name = "menu_page" />
<frame src = "/html/main.htm" name = "main_page" />
<noframes>
<body>Your browser does not support frames.</body>
</noframes>
</frameset>
</html>在此，我们创建了两列以填充两个框架。第一个框架宽 200 像素，并将包含 menu.htm 文件实现的导航菜单栏。第二列填充剩余空间，并且将包含页面的主要部分，它由 main.htm 文件实现。对于菜单栏中所有三个可用的链接，我们已将目标框架指定为 main_page ，因此无论何时您单击菜单栏中的任何链接，可用的链接都将在主页中打开。
Here, we have created two columns to fill with two frames. The first frame is 200 pixels wide and will contain the navigation menu bar implemented by menu.htm file. The second column fills in remaining space and will contain the main part of the page and it is implemented by main.htm file. For all the three links available in menu bar, we have mentioned target frame as main_page, so whenever you click any of the links in menu bar, available link will open in main page.
以下是 menu.htm 文件的内容
Following is the content of menu.htm file
<!DOCTYPE html>
<html>
<body bgcolor = "#4a7d49">
<a href = "https://www.google.com" target = "main_page">Google</a>
<br />
<br />
<a href = "https://www.microsoft.com" target = "main_page">Microsoft</a>
<br />
<br />
<a href = "http://news.bbc.co.uk" target = "main_page">BBC News</a>
</body>
</html>以下是 main.htm 文件的内容 −
Following is the content of main.htm file −
<!DOCTYPE html>
<html>
<body bgcolor = "#b5dcb3">
<h3>This is main page and content from any link will be displayed here.</h3>
<p>So now click any link and see the result.</p>
</body>
</html>当我们加载 test.htm 文件时，它会产生以下结果 −
When we load test.htm file, it produces following result −
现在，您可以尝试单击左侧面板中提供的链接并查看结果。targetattribute 还可以采用以下值之一 −
Now you can try to click links available in the left panel and see the result. The targetattribute can also take one of the following values −
Sr.No |
Option & Description |
1 |
_self Loads the page into the current frame. |
2 |
_blank Loads a page into a new browser window. Opening a new window. |
3 |
_parent Loads the page into the parent window, which in the case of a single frameset is the main browser window. |
4 |
_top Loads the page into the browser window, replacing any current frames. |
5 |
targetframe Loads the page into a named targetframe. |
HTML - Iframes
可以使用 HTML 标记 <iframe> 定义内联框架。 <iframe> 标记与 <frameset> 标记无关，而是可以出现在文档中的任何位置。 <iframe> 标记在文档中定义一个矩形区域，浏览器可以在其中显示一个单独的文档，包括滚动条和边框。内联框架用于在当前 HTML 文档中嵌入另一个文档。
You can define an inline frame with HTML tag <iframe>. The <iframe> tag is not somehow related to <frameset> tag, instead, it can appear anywhere in your document. The <iframe> tag defines a rectangular region within the document in which the browser can display a separate document, including scrollbars and borders. An inline frame is used to embed another document within the current HTML document.
src 属性用于指定占据内联框架的文档的 URL。
The src attribute is used to specify the URL of the document that occupies the inline frame.
Example
以下是显示如何使用 <iframe> 的示例：
Following is the example to show how to use the <iframe> −
<!DOCTYPE html>
<html>
<head>
<title>HTML Iframes</title>
</head>
<body>
<p>Document content goes here...</p>
<iframe src = "/html/menu.htm" width = "555" height = "200">
Sorry your browser does not support inline frames.
</iframe>
<p>Document content also go here...</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The <Iframe> Tag Attributes
<iframe> 标记的大多数属性，包括 name、class、frameborder、id、longdesc、marginheight、marginwidth、name、scrolling、style 和 title 的行为就像 <frame> 标记的相应属性。
Most of the attributes of the <iframe> tag, including name, class, frameborder, id, longdesc, marginheight, marginwidth, name, scrolling, style, and title behave exactly like the corresponding attributes for the <frame> tag.
Sr.No |
Attribute & Description |
1 |
src This attribute is used to give the file name that should be loaded in the frame. Its value can be any URL. For example, src = "/html/top_frame.htm" will load an HTML file available in html directory. |
2 |
name This attribute allows you to give a name to a frame. It is used to indicate which frame a document should be loaded into. This is especially important when you want to create links in one frame that load pages into an another frame, in which case the second frame needs a name to identify itself as the target of the link. |
3 |
frameborder This attribute specifies whether or not the borders of that frame are shown; it overrides the value given in the frameborder attribute on the <frameset> tag if one is given, and this can take values either 1 (yes) or 0 (no). |
4 |
marginwidth This attribute allows you to specify the width of the space between the left and right of the frame’s borders and the frame’s content. The value is given in pixels. For example marginwidth = "10". |
5 |
marginheight This attribute allows you to specify the height of the space between the top and bottom of the frame’s borders and its contents. The value is given in pixels. For example marginheight = "10". |
6 |
height This attribute specifies the height of <iframe>. |
7 |
scrolling This attribute controls the appearance of the scrollbars that appear on the frame. This takes values either "yes", "no" or "auto". For example scrolling = "no" means it should not have scroll bars. |
8 |
longdesc This attribute allows you to provide a link to another page containing a long description of the contents of the frame. For example longdesc = "framedescription.htm" |
9 |
width This attribute specifies the width of <iframe>. |
HTML - Blocks
所有 HTML 元素都可以分为两类 (a) 块级元素 *(b)*内联元素。
All the HTML elements can be categorized into two categories (a) Block Level Elements *(b)*Inline Elements.
Block Elements
块级元素出现在屏幕上，就好像它们前后都有一个换行符。例如，<p>、<h1>、<h2>、<h3>、<h4>、<h5>、<h6>、<ul>、<ol>、<dl>、<pre>、<hr />、<blockquote>、<address> 元素都是块级元素。它们都从自己的新行开始，任何紧随其后的元素都会出现在它自己的新行中。
Block elements appear on the screen as if they have a line break before and after them. For example, the <p>, <h1>, <h2>, <h3>, <h4>, <h5>, <h6>, <ul>, <ol>, <dl>, <pre>, <hr />, <blockquote>, and <address> elements are all block level elements. They all start on their own new line, and anything that follows them appears on its own new line.
Inline Elements
另一方面，内联元素可以出现在句子中，不必出现在它们自己的新行中。<b>、<i>、<u>、<em>、<strong>、<sup>、<sub>、<big>、<small>、<li>、<ins>、<del>、<code>、<cite>、<dfn>、<kbd> 和 <var> 元素都是内联元素。
Inline elements, on the other hand, can appear within sentences and do not have to appear on a new line of their own. The <b>, <i>, <u>, <em>, <strong>, <sup>, <sub>, <big>, <small>, <li>, <ins>, <del>, <code>, <cite>, <dfn>, <kbd>, and <var> elements are all inline elements.
Grouping HTML Elements
有两个重要的标记我们经常用于对各种其他 HTML 标记进行分组，即 (i) <div> 标记和 (ii) <span> 标记
There are two important tags which we use very frequently to group various other HTML tags (i) <div> tag and (ii) <span> tag
The <div> tag
这是一个非常重要的块级标记，它在对各种其他 HTML 标记进行分组并在元素组上应用 CSS 方面发挥着重要作用。即使现在 <div> 标记也可以用于创建网页布局，我们在其中使用 <div> 标记来定义页面的不同部分（左、右、上等）。该标记不会对块进行任何视觉更改，但在与 CSS 一起使用时则更有意义。
This is the very important block level tag which plays a big role in grouping various other HTML tags and applying CSS on group of elements. Even now <div> tag can be used to create webpage layout where we define different parts (Left, Right, Top etc.) of the page using <div> tag. This tag does not provide any visual change on the block but this has more meaning when it is used with CSS.
Example
以下是 <div> 标记的一个简单示例。我们将在单独的章节学习层叠样式表 (CSS)，但我们在此处使用它演示 <div> 标记的用法：
Following is a simple example of <div> tag. We will learn Cascading Style Sheet (CSS) in a separate chapter but we used it here to show the usage of <div> tag −
<!DOCTYPE html>
<html>
<head>
<title>HTML div Tag</title>
</head>
<body>
<!-- First group of tags -->
<div style = "color:red">
<h4>This is first group</h4>
<p>Following is a list of vegetables</p>
<ul>
<li>Beetroot</li>
<li>Ginger</li>
<li>Potato</li>
<li>Radish</li>
</ul>
</div>
<!-- Second group of tags -->
<div style = "color:green">
<h4>This is second group</h4>
<p>Following is a list of fruits</p>
<ul>
<li>Apple</li>
<li>Banana</li>
<li>Mango</li>
<li>Strawberry</li>
</ul>
</div>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The <span> tag
HTML <span> 是一个内联元素，可用于对 HTML 文档中的内联元素进行分组。该标记也不会对块进行任何视觉更改，但在与 CSS 一起使用时则更有意义。
The HTML <span> is an inline element and it can be used to group inline-elements in an HTML document. This tag also does not provide any visual change on the block but has more meaning when it is used with CSS.
<span> 标记和 <div> 标记之间的区别在于，<span> 标记用于内联元素，而 <div> 标记用于块级元素。
The difference between the <span> tag and the <div> tag is that the <span> tag is used with inline elements whereas the <div> tag is used with block-level elements.
Example
以下是 <span> 标记的一个简单示例。我们将在单独的章节学习层叠样式表 (CSS)，但我们在此处使用它演示 <span> 标记的用法：
Following is a simple example of <span> tag. We will learn Cascading Style Sheet (CSS) in a separate chapter but we used it here to show the usage of <span> tag −
<!DOCTYPE html>
<html>
<head>
<title>HTML span Tag</title>
</head>
<body>
<p>This is <span style = "color:red">red</span> and this is
<span style = "color:green">green</span></p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Backgrounds
默认情况下，您的网页背景为白色。您可能不喜欢它，但不用担心。HTML 为您提供了以下两种很好的方式来装饰您的网页背景。
By default, your webpage background is white in color. You may not like it, but no worries. HTML provides you following two good ways to decorate your webpage background.
-
HTML Background with Colors
-
HTML Background with Images
现在，让我们使用适当的示例逐一了解这两种方法。
Now let’s see both the approaches one by one using appropriate examples.
Html Background with Colors
bgcolor 属性用于控制 HTML 元素的背景，特别是页面主体和表格背景。
The bgcolor attribute is used to control the background of an HTML element, specifically page body and table backgrounds.
以下是有任何 HTML 标签的语法以使用 bgcolor 属性。
Following is the syntax to use bgcolor attribute with any HTML tag.
<tagname bgcolor = "color_value"...>color_value 可以通过以下任何格式指定 −
This color_value can be given in any of the following formats −
<!-- Format 1 - Use color name -->
<table bgcolor = "lime" >
<!-- Format 2 - Use hex value -->
<table bgcolor = "#f1f1f1" >
<!-- Format 3 - Use color value in RGB terms -->
<table bgcolor = "rgb(0,0,120)" >Example
以下是可以设置 HTML 标签背景的示例 −
Here are the examples to set background of an HTML tag −
<!DOCTYPE html>
<html>
<head>
<title>HTML Background Colors</title>
</head>
<body>
<!-- Format 1 - Use color name -->
<table bgcolor = "yellow" width = "100%">
<tr>
<td>
This background is yellow
</td>
</tr>
</table>
<!-- Format 2 - Use hex value -->
<table bgcolor = "#6666FF" width = "100%">
<tr>
<td>
This background is sky blue
</td>
</tr>
</table>
<!-- Format 3 - Use color value in RGB terms -->
<table bgcolor = "rgb(255,0,255)" width = "100%">
<tr>
<td>
This background is green
</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Html Background with Images
background 属性也可以用于控制 HTML 元素的背景，特别是页面主体和表格背景。您可以指定图像来设置 HTML 页面或表格的背景。
The background attribute can also be used to control the background of an HTML element, specifically page body and table backgrounds. You can specify an image to set background of your HTML page or table.
以下是有任何 HTML 标签的语法以使用 background 属性。
Following is the syntax to use background attribute with any HTML tag.
<tagname background = "Image URL"...>最常使用的图像格式是 JPEG、GIF 和 PNG 图像。
The most frequently used image formats are JPEG, GIF and PNG images.
Example
以下是可以设置表格背景图像的示例。
Here are the examples to set background images of a table.
<!DOCTYPE html>
<html>
<head>
<title>HTML Background Images</title>
</head>
<body>
<!-- Set table background -->
<table background = "/images/html.gif" width = "100%" height = "100">
<tr><td>
This background is filled up with HTML image.
</td></tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Patterned & Transparent Backgrounds
你可能在不同的网站上看到过许多图案或透明背景。这可以通过在背景中使用图案图像或透明图像轻松实现。
You might have seen many pattern or transparent backgrounds on various websites. This simply can be achieved by using patterned image or transparent image in the background.
建议在创建图案或透明的 GIF 或 PNG 图像时，使用尽可能小的尺寸，甚至像 1x1 这样的尺寸以避免加载缓慢。
It is suggested that while creating patterns or transparent GIF or PNG images, use the smallest dimensions possible even as small as 1x1 to avoid slow loading.
Example
以下是可以设置表格的背景图案的示例 −
Here are the examples to set background pattern of a table −
<!DOCTYPE html>
<html>
<head>
<title>HTML Background Images</title>
</head>
<body>
<!-- Set a table background using pattern -->
<table background = "/images/pattern1.gif" width = "100%" height = "100">
<tr>
<td>
This background is filled up with a pattern image.
</td>
</tr>
</table>
<!-- Another example on table background using pattern -->
<table background = "/images/pattern2.gif" width = "100%" height = "100">
<tr>
<td>
This background is filled up with a pattern image.
</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Colors
颜色在给你的网站赋予良好的观感方面非常重要。你可以使用 <body> 标签在页面级别指定颜色，也可以使用 bgcolor 属性为单个标签设置颜色。
Colors are very important to give a good look and feel to your website. You can specify colors on page level using <body> tag or you can set colors for individual tags using bgcolor attribute.
<body> 标签具有以下属性，可用于设置不同的颜色 −
The <body> tag has following attributes which can be used to set different colors −
-
bgcolor − sets a color for the background of the page.
-
text − sets a color for the body text.
-
alink − sets a color for active links or selected links.
-
link − sets a color for linked text.
-
vlink − sets a color for visited links − that is, for linked text that you have already clicked on.
HTML Color Coding Methods
有以下三种不同的方法可以在你的网页中设置颜色 −
There are following three different methods to set colors in your web page −
-
Color names − You can specify color names directly like green, blue or red.
-
Hex codes − A six-digit code representing the amount of red, green, and blue that makes up the color.
-
Color decimal or percentage values − This value is specified using the rgb( ) property.
现在我们将逐一了解这些着色方案。
Now we will see these coloring schemes one by one.
HTML Colors - Color Names
您可以直接指定一个颜色名称来设置文本或背景颜色。W3C 列出了 16 个基本颜色名称，可通过 HTML 验证器进行验证，但主要浏览器支持 200 多个不同的颜色名称。
You can specify direct a color name to set text or background color. W3C has listed 16 basic color names that will validate with an HTML validator but there are over 200 different color names supported by major browsers.
Note − 查看 HTML Color Name. 的完整列表
Note − Check a complete list of HTML Color Name.
W3C Standard 16 Colors
以下是 W3C 标准 16 种颜色的名称列表，建议使用它们。
Here is the list of W3C Standard 16 Colors names and it is recommended to use them.
Black |
Gray |
Silver |
White |
||||
Yellow |
Lime |
Aqua |
Fuchsia |
||||
Red |
Green |
Blue |
Purple |
||||
Maroon |
Olive |
Navy |
Teal |
Example
以下是在 HTML 标记中按颜色名称设置背景的示例 −
Here are the examples to set background of an HTML tag by color name −
<!DOCTYPE html>
<html>
<head>
<title>HTML Colors by Name</title>
</head>
<body text = "blue" bgcolor = "green">
<p>Use different color names for for body and table and see the result.</p>
<table bgcolor = "black">
<tr>
<td>
<font color = "white">This text will appear white on black background.</font>
</td>
</tr>
</table>
</body>
</html>HTML Colors - Hex Codes
十六进制数是一种包含 6 位数字的颜色表示形式。前两位数字 (RR) 表示红色值，后两位表示绿色值 (GG)，最后两位表示蓝色值 (BB)。
A hexadecimal is a 6 digit representation of a color. The first two digits(RR) represent a red value, the next two are a green value(GG), and the last are the blue value(BB).
16 进制值可以来自任何图形软件，如 Adobe Photoshop、Paintshop Pro 或 MS Paint。
A hexadecimal value can be taken from any graphics software like Adobe Photoshop, Paintshop Pro or MS Paint.
每个十六进制代码之前都会有一个磅或哈希符号 #。下面列出了一些使用十六进制表示法的颜色。
Each hexadecimal code will be preceded by a pound or hash sign #. Following is a list of few colors using hexadecimal notation.
Color |
Color HEX |
#000000 |
|
#FF0000 |
|
#00FF00 |
|
#0000FF |
|
#FFFF00 |
|
#00FFFF |
|
#FF00FF |
|
#C0C0C0 |
|
#FFFFFF |
Example
以下是在 HTML 标记中按十六进制颜色代码设置背景的示例 −
Here are the examples to set background of an HTML tag by color code in hexadecimal −
<!DOCTYPE html>
<html>
<head>
<title>HTML Colors by Hex</title>
</head>
<body text = "#0000FF" bgcolor = "#00FF00">
<p>Use different color hexa for for body and table and see the result.</p>
<table bgcolor = "#000000">
<tr>
<td>
<font color = "#FFFFFF">This text will appear white on black background.</font>
</td>
</tr>
</table>
</body>
</html>HTML Colors - RGB Values
此颜色值使用 rgb( ) 属性指定。该属性采用三个值，分别对应红色、绿色和蓝色。该值可以是介于 0 到 255 之间的整数或百分比。
This color value is specified using the rgb( ) property. This property takes three values, one each for red, green, and blue. The value can be an integer between 0 and 255 or a percentage.
以下列表显示了使用 RGB 值的一些颜色。
Following is a list to show few colors using RGB values.
Color |
Color RGB |
rgb(0,0,0) |
|
rgb(255,0,0) |
|
rgb(0,255,0) |
|
rgb(0,0,255) |
|
rgb(255,255,0) |
|
rgb(0,255,255) |
|
rgb(255,0,255) |
|
rgb(192,192,192) |
|
rgb(255,255,255) |
Example
以下是在 HTML 标记中按 rgb() 值设置背景颜色代码的示例 −
Here are the examples to set background of an HTML tag by color code using rgb() values −
<!DOCTYPE html>
<html>
<head>
<title>HTML Colors by RGB code</title>
</head>
<body text = "rgb(0,0,255)" bgcolor = "rgb(0,255,0)">
<p>Use different color code for for body and table and see the result.</p>
<table bgcolor = "rgb(0,0,0)">
<tr>
<td>
<font color = "rgb(255,255,255)">This text will appear white on black background.</font>
</td>
</tr>
</table>
</body>
</html>Browser Safe Colors
以下是 216 种颜色的列表，这些颜色应该是最安全的计算机无关颜色。这些颜色的十六进制代码从 000000 到 FFFFFF，并且它们将得到所有具有 256 色调色板的计算机的支持。
Here is the list of 216 colors which are supposed to be safest and computer independent colors. These colors very from hexa code 000000 to FFFFFF and they will be supported by all the computers having 256 color palette.
000000 |
000033 |
000066 |
000099 |
0000CC |
0000FF |
003300 |
003333 |
003366 |
003399 |
0033CC |
0033FF |
006600 |
006633 |
006666 |
006699 |
0066CC |
0066FF |
009900 |
009933 |
009966 |
009999 |
0099CC |
0099FF |
00CC00 |
00CC33 |
00CC66 |
00CC99 |
00CCCC |
00CCFF |
00FF00 |
00FF33 |
00FF66 |
00FF99 |
00FFCC |
00FFFF |
330000 |
330033 |
330066 |
330099 |
3300CC |
3300FF |
333300 |
333333 |
333366 |
333399 |
3333CC |
3333FF |
336600 |
336633 |
336666 |
336699 |
3366CC |
3366FF |
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FFFFFF |
HTML - Fonts
字体在使网站更易于用户使用和提高内容可读性方面起着非常重要的作用。字体和颜色完全取决于用来查看您网页的计算机和浏览器，但可以使用 HTML <font> 标记在您网站上为文本添加样式、大小和颜色。你可以使用 <basefont> 标记将所有文本设置成相同的大小、字体和颜色。
Fonts play a very important role in making a website more user friendly and increasing content readability. Font face and color depends entirely on the computer and browser that is being used to view your page but you can use HTML <font> tag to add style, size, and color to the text on your website. You can use a <basefont> tag to set all of your text to the same size, face, and color.
font 标记具有名为 size, color 和 face 的三个属性，用于自定义您的字体。要在网页中随时更改任何字体属性，只需使用 <font> 标记。后面的文本将保持更改状态，直到用 </font> 标记关闭为止。您可以在一个 <font> 标记中更改一个或全部字体属性。
The font tag is having three attributes called size, color, and face to customize your fonts. To change any of the font attributes at any time within your webpage, simply use the <font> tag. The text that follows will remain changed until you close with the </font> tag. You can change one or all of the font attributes within one <font> tag.
Set Font Size
您可以使用 size 属性设置内容字体大小。可接受的值范围为 1（最小）到 7（最大）。字体的默认大小为 3。
You can set content font size using size attribute. The range of accepted values is from 1(smallest) to 7(largest). The default size of a font is 3.
Example
<!DOCTYPE html>
<html>
<head>
<title>Setting Font Size</title>
</head>
<body>
<font size = "1">Font size = "1"</font><br />
<font size = "2">Font size = "2"</font><br />
<font size = "3">Font size = "3"</font><br />
<font size = "4">Font size = "4"</font><br />
<font size = "5">Font size = "5"</font><br />
<font size = "6">Font size = "6"</font><br />
<font size = "7">Font size = "7"</font>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Relative Font Size
您可以指定比预设字体大小大多少个尺寸或小多少个尺寸。您可以像 <font size = "+n"> 或 <font size = "−n"> 那样指定它
You can specify how many sizes larger or how many sizes smaller than the preset font size should be. You can specify it like <font size = "+n"> or <font size = "−n">
Example
<!DOCTYPE html>
<html>
<head>
<title>Relative Font Size</title>
</head>
<body>
<font size = "-1">Font size = "-1"</font><br />
<font size = "+1">Font size = "+1"</font><br />
<font size = "+2">Font size = "+2"</font><br />
<font size = "+3">Font size = "+3"</font><br />
<font size = "+4">Font size = "+4"</font>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Setting Font Face
您可以使用 face 属性设置字体，但请注意，如果查看该页面的用户未安装该字体，则他们将无法看到它。相反，用户将看到适用于用户计算机的默认字体。
You can set font face using face attribute but be aware that if the user viewing the page doesn’t have the font installed, they will not be able to see it. Instead user will see the default font face applicable to the user’s computer.
Example
<!DOCTYPE html>
<html>
<head>
<title>Font Face</title>
</head>
<body>
<font face = "Times New Roman" size = "5">Times New Roman</font><br />
<font face = "Verdana" size = "5">Verdana</font><br />
<font face = "Comic sans MS" size =" 5">Comic Sans MS</font><br />
<font face = "WildWest" size = "5">WildWest</font><br />
<font face = "Bedrock" size = "5">Bedrock</font><br />
</body>
</html>这会产生以下结果 −
This will produce the following result −
Specify alternate font faces
只有当访问者的计算机上安装了您的字体时，他们才能看到您的字体。因此，您可以通过列出用逗号分隔的字体名称来指定两个或更多字体替代项。
A visitor will only be able to see your font if they have that font installed on their computer. So, it is possible to specify two or more font face alternatives by listing the font face names, separated by a comma.
<font face = "arial,helvetica">
<font face = "Lucida Calligraphy,Comic Sans MS,Lucida Console">页面加载后，其浏览器将显示可用的第一个字体系列。如果未安装上面列出的字体，它将显示默认字体系列 Times New Roman。
When your page is loaded, their browser will display the first font face available. If none of the given fonts are installed, then it will display the default font face Times New Roman.
Note − 查看 HTML Standard Fonts 的完整列表。
Note − Check a complete list of HTML Standard Fonts.
Setting Font Color
您可以使用 color 属性设置任何您喜欢的字体颜色。您可以通过颜色名称或十六进制代码来指定所需的颜色。
You can set any font color you like using color attribute. You can specify the color that you want by either the color name or hexadecimal code for that color.
Note – 您可以查看一整份 HTML Color Name with Codes 的列表。
Note − You can check a complete list of HTML Color Name with Codes.
The <basefont> Element
<basefont> 元素用来为文档中未包含在 <font> 标记内的任何部分设置默认字体大小、颜色和字体类型。您可以使用 <font> 元素来覆盖 <basefont> 设置。
The <basefont> element is supposed to set a default font size, color, and typeface for any parts of the document that are not otherwise contained within a <font> tag. You can use the <font> elements to override the <basefont> settings.
<basefont> 标记还接受 color、size 和 face 属性，并且可以通过为 size 指定值 +1 来支持相对字体设置（表示较大一号）或 -2（表示较小两号）。
The <basefont> tag also takes color, size and face attributes and it will support relative font setting by giving size a value of +1 for a size larger or −2 for two sizes smaller.
Example
<!DOCTYPE html>
<html>
<head>
<title>Setting Basefont Color</title>
</head>
<body>
<basefont face = "arial, verdana, sans-serif" size = "2" color = "#ff0000">
<p>This is the page's default font.</p>
<h2>Example of the <basefont> Element</h2>
<p><font size = "+2" color = "darkgray">
This is darkgray text with two sizes larger
</font>
</p>
<p><font face = "courier" size = "-1" color = "#000000">
It is a courier font, a size smaller and black in color.
</font>
</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Forms
当您希望从网站访问者那里收集一些数据时，HTML 表单是必需的。例如，在用户注册过程中，您可能想要收集姓名、电子邮件地址、信用卡等信息。
HTML Forms are required, when you want to collect some data from the site visitor. For example, during user registration you would like to collect information such as name, email address, credit card, etc.
表单将从网站访问者那里获取输入，然后将其发布到后端应用程序，如 CGI、ASP 脚本或 PHP 脚本等。后端应用程序将根据应用程序内部定义的业务逻辑对传入的数据执行必需的处理。
A form will take input from the site visitor and then will post it to a back-end application such as CGI, ASP Script or PHP script etc. The back-end application will perform required processing on the passed data based on defined business logic inside the application.
有各种可用的表单元素，如文本字段、文本区域字段、下拉菜单、单选按钮、复选框等。
There are various form elements available like text fields, textarea fields, drop-down menus, radio buttons, checkboxes, etc.
HTML <form> 标记用于创建 HTML 表单，其语法如下 -
The HTML <form> tag is used to create an HTML form and it has following syntax −
<form action = "Script URL" method = "GET|POST">
form elements like input, textarea etc.
</form>Form Attributes
除了通用属性外，下表是最常用的表单属性的列表 -
Apart from common attributes, following is a list of the most frequently used form attributes −
Sr.No |
Attribute & Description |
1 |
action Backend script ready to process your passed data. |
2 |
method Method to be used to upload data. The most frequently used are GET and POST methods. |
3 |
target Specify the target window or frame where the result of the script will be displayed. It takes values like _blank, _self, _parent etc. |
4 |
enctype You can use the enctype attribute to specify how the browser encodes the data before it sends it to the server. Possible values are − application/x-www-form-urlencoded − This is the standard method most forms use in simple scenarios. mutlipart/form-data − This is used when you want to upload binary data in the form of files like image, word file etc. |
Note - 您可以参考 Perl & CGI 来详细了解表单数据上传的工作原理。
Note − You can refer to Perl & CGI for a detail on how form data upload works.
HTML Form Controls
有不同类型的表单控件，您可以使用它们来使用 HTML 表单收集数据 -
There are different types of form controls that you can use to collect data using HTML form −
-
Text Input Controls
-
Checkboxes Controls
-
Radio Box Controls
-
Select Box Controls
-
File Select boxes
-
Hidden Controls
-
Clickable Buttons
-
Submit and Reset Button
Text Input Controls
表单上使用三种类型的文本输入 -
There are three types of text input used on forms −
-
Single-line text input controls − This control is used for items that require only one line of user input, such as search boxes or names. They are created using HTML <input> tag.
-
Password input controls − This is also a single-line text input but it masks the character as soon as a user enters it. They are also created using HTMl <input> tag.
-
Multi-line text input controls − This is used when the user is required to give details that may be longer than a single sentence. Multi-line input controls are created using HTML <textarea> tag.
Single-line text input controls
此控件用于所需要用户输入单行的项目，比如搜索框或者姓名。用 HTML <input> 标签创建。<br><br>
This control is used for items that require only one line of user input, such as search boxes or names. They are created using HTML <input> tag.
Example
以下是用于获取姓名的单行文本输入的基本示例：<br><br>
Here is a basic example of a single-line text input used to take first name and last name −
<!DOCTYPE html>
<html>
<head>
<title>Text Input Control</title>
</head>
<body>
<form >
First name: <input type = "text" name = "first_name" />
<br>
Last name: <input type = "text" name = "last_name" />
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是用于创建文本字段的 <input> 标签的属性列表：<br><br>
Following is the list of attributes for <input> tag for creating text field.
Sr.No |
Attribute & Description |
1 |
type Indicates the type of input control and for text input control it will be set to text. |
2 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
3 |
value This can be used to provide an initial value inside the control. |
4 |
size Allows to specify the width of the text-input control in terms of characters. |
5 |
maxlength Allows to specify the maximum number of characters a user can enter into the text box. |
Password input controls
这也是单行文本输入，但用户输入后会屏蔽字符。也是用 HTML <input> 标签创建，但 type 属性设置为 password 。<br><br>
This is also a single-line text input but it masks the character as soon as a user enters it. They are also created using HTML <input>tag but type attribute is set to password.
Example
以下是用于获取用户密码的单行密码输入的基本示例：<br><br>
Here is a basic example of a single-line password input used to take user password −
<!DOCTYPE html>
<html>
<head>
<title>Password Input Control</title>
</head>
<body>
<form >
User ID : <input type = "text" name = "user_id" />
<br>
Password: <input type = "password" name = "password" />
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是用于创建密码字段的 <input> 标签的属性列表：<br><br>
Following is the list of attributes for <input> tag for creating password field.
Sr.No |
Attribute & Description |
1 |
type Indicates the type of input control and for password input control it will be set to password. |
2 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
3 |
value This can be used to provide an initial value inside the control. |
4 |
size Allows to specify the width of the text-input control in terms of characters. |
5 |
maxlength Allows to specify the maximum number of characters a user can enter into the text box. |
Multiple-Line Text Input Controls
当用户需要提供可能长于单一语句的详细信息时使用。使用 HTML <textarea> 标签创建多行输入控件。<br><br>
This is used when the user is required to give details that may be longer than a single sentence. Multi-line input controls are created using HTML <textarea> tag.
Example
以下是用于获取商品说明的多行文本输入的基本示例：<br><br>
Here is a basic example of a multi-line text input used to take item description −
<!DOCTYPE html>
<html>
<head>
<title>Multiple-Line Input Control</title>
</head>
<body>
<form>
Description : <br />
<textarea rows = "5" cols = "50" name = "description">
Enter description here...
</textarea>
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是 <textarea> 标签的属性列表：<br><br>
Following is the list of attributes for <textarea> tag.
Sr.No |
Attribute & Description |
1 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
2 |
rows Indicates the number of rows of text area box. |
3 |
cols Indicates the number of columns of text area box |
Checkbox Control
当需要选择多个选项时，使用复选框。也使用 HTML <input> 标签创建，但 type 属性设置为 checkbox. 。<br><br>
Checkboxes are used when more than one option is required to be selected. They are also created using HTML <input> tag but type attribute is set to checkbox..
Example
以下是带有两个复选框的表单的 HTML 代码示例：
Here is an example HTML code for a form with two checkboxes −
<!DOCTYPE html>
<html>
<head>
<title>Checkbox Control</title>
</head>
<body>
<form>
<input type = "checkbox" name = "maths" value = "on"> Maths
<input type = "checkbox" name = "physics" value = "on"> Physics
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是用于 <checkbox> 标签的属性列表。
Following is the list of attributes for <checkbox> tag.
Sr.No |
Attribute & Description |
1 |
type Indicates the type of input control and for checkbox input control it will be set to checkbox.. |
2 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
3 |
value The value that will be used if the checkbox is selected. |
4 |
checked Set to checked if you want to select it by default. |
Radio Button Control
当从许多选项中只要求选择一个选项时，将使用单选按钮。它也是利用 HTML <input> 标签创建的，但类型属性设置为 radio 。
Radio buttons are used when out of many options, just one option is required to be selected. They are also created using HTML <input> tag but type attribute is set to radio.
Example
这是一个包含两个单选按钮的表单的示例 HTML 代码−
Here is example HTML code for a form with two radio buttons −
<!DOCTYPE html>
<html>
<head>
<title>Radio Box Control</title>
</head>
<body>
<form>
<input type = "radio" name = "subject" value = "maths"> Maths
<input type = "radio" name = "subject" value = "physics"> Physics
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是用于单选按钮的属性列表。
Following is the list of attributes for radio button.
Sr.No |
Attribute & Description |
1 |
type Indicates the type of input control and for checkbox input control it will be set to radio. |
2 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
3 |
value The value that will be used if the radio box is selected. |
4 |
checked Set to checked if you want to select it by default. |
Select Box Control
一个选择框，也称为下拉框，它提供了将各种选项以下拉列表形式列出的选项，用户可以从中选择一个或多个选项。
A select box, also called drop down box which provides option to list down various options in the form of drop down list, from where a user can select one or more options.
Example
这里有一个用于带有下拉框的表单的 HTML 代码示例
Here is example HTML code for a form with one drop down box
<!DOCTYPE html>
<html>
<head>
<title>Select Box Control</title>
</head>
<body>
<form>
<select name = "dropdown">
<option value = "Maths" selected>Maths</option>
<option value = "Physics">Physics</option>
</select>
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是 <select> 标签的重要属性列表 -
Following is the list of important attributes of <select> tag −
Sr.No |
Attribute & Description |
1 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
2 |
size This can be used to present a scrolling list box. |
3 |
multiple If set to "multiple" then allows a user to select multiple items from the menu. |
以下是 <option> 标签的重要属性列表 -
Following is the list of important attributes of <option> tag −
Sr.No |
Attribute & Description |
1 |
value The value that will be used if an option in the select box box is selected. |
2 |
selected Specifies that this option should be the initially selected value when the page loads. |
3 |
label An alternative way of labeling options |
File Upload Box
如果你想允许用户将一个文件上传至你的网站，则需要使用一个文件上传框，也称为一个文件选择框。这个也使用 <input> 元素创建，但类型属性设置为 file 。
If you want to allow a user to upload a file to your web site, you will need to use a file upload box, also known as a file select box. This is also created using the <input> element but type attribute is set to file.
Example
这里有一个用于带有一个文件上传框的表单的 HTML 代码示例 -
Here is example HTML code for a form with one file upload box −
<!DOCTYPE html>
<html>
<head>
<title>File Upload Box</title>
</head>
<body>
<form>
<input type = "file" name = "fileupload" accept = "image/*" />
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Attributes
以下是文件上传框的重要属性列表 −
Following is the list of important attributes of file upload box −
Sr.No |
Attribute & Description |
1 |
name Used to give a name to the control which is sent to the server to be recognized and get the value. |
2 |
accept Specifies the types of files that the server accepts. |
Button Controls
在 HTML 中有各种创建可点击按钮的方法。您还可以使用 <input> 标签创建可点击按钮，方法是将它的类型属性设置为 button 。类型属性可以取以下值 −
There are various ways in HTML to create clickable buttons. You can also create a clickable button using <input>tag by setting its type attribute to button. The type attribute can take the following values −
Sr.No |
Type & Description |
1 |
submit This creates a button that automatically submits a form. |
2 |
reset This creates a button that automatically resets form controls to their initial values. |
3 |
button This creates a button that is used to trigger a client-side script when the user clicks that button. |
4 |
image This creates a clickable button but we can use an image as background of the button. |
Example
以下是在使用 HTML 代码类型创建按钮的示例 −
Here is example HTML code for a form with three types of buttons −
<!DOCTYPE html>
<html>
<head>
<title>File Upload Box</title>
</head>
<body>
<form>
<input type = "submit" name = "submit" value = "Submit" />
<input type = "reset" name = "reset" value = "Reset" />
<input type = "button" name = "ok" value = "OK" />
<input type = "image" name = "imagebutton" src = "/html/images/logo.png" />
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Hidden Form Controls
隐藏表单控件用于在页面中隐藏数据，这些数据稍后可推送到服务器。此控件隐藏在代码中，不会显示在实际页面上。例如，下面隐藏的表单用于保存当前页号。当用户单击下一页时，隐藏控件的值将被发送到 Web 服务器，Web 服务器将根据传入的当前页来决定接下来显示哪个页面。
Hidden form controls are used to hide data inside the page which later on can be pushed to the server. This control hides inside the code and does not appear on the actual page. For example, following hidden form is being used to keep current page number. When a user will click next page then the value of hidden control will be sent to the web server and there it will decide which page will be displayed next based on the passed current page.
Example
下面是展示如何使用隐藏控件的 HTML 代码示例 −
Here is example HTML code to show the usage of hidden control −
<!DOCTYPE html>
<html>
<head>
<title>File Upload Box</title>
</head>
<body>
<form>
<p>This is page 10</p>
<input type = "hidden" name = "pagename" value = "10" />
<input type = "submit" name = "submit" value = "Submit" />
<input type = "reset" name = "reset" value = "Reset" />
</form>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Embed Multimedia
有时您需要在网页中添加音乐或视频。向您的网站添加视频或声音最简单的方法是包括特殊的 HTML 标签 <embed> 。当浏览器本身支持 <embed> 标签和给定的媒体类型时，此标签会导致浏览器自动包含控件以供多媒体使用。
Sometimes you need to add music or video into your web page. The easiest way to add video or sound to your web site is to include the special HTML tag called <embed>. This tag causes the browser itself to include controls for the multimedia automatically provided browser supports <embed> tag and given media type.
您还可以在不识别 <embed> 标签的浏览器中包含 <noembed> 标签。例如，您可以使用 <embed> 来显示您选择的电影，当浏览器不支持 <embed> 标签时，使用 <noembed> 来显示单个 JPG 图像。
You can also include a <noembed> tag for the browsers which don’t recognize the <embed> tag. You could, for example, use <embed> to display a movie of your choice, and <noembed> to display a single JPG image if browser does not support <embed> tag.
Example
以下是播放嵌入 MIDI 文件的简单示例 −
Here is a simple example to play an embedded midi file −
<!DOCTYPE html>
<html>
<head>
<title>HTML embed Tag</title>
</head>
<body>
<embed src = "/html/yourfile.mid" width = "100%" height = "60" >
<noembed><img src = "yourimage.gif" alt = "Alternative Media" ></noembed>
</embed>
</body>
</html>The <embed> Tag Attributes
以下是可用于 <embed> 标签的重要属性列表。
Following is the list of important attributes which can be used with <embed> tag.
Sr.No |
Attribute & Description |
1 |
align Determines how to align the object. It can be set to either center, left or right. |
2 |
autostart This boolean attribute indicates if the media should start automatically. You can set it either true or false. |
3 |
loop Specifies if the sound should be played continuously (set loop to true), a certain number of times (a positive value) or not at all (false) |
4 |
playcount Specifies the number of times to play the sound. This is alternate option for loop if you are usiong IE. |
5 |
hidden Specifies if the multimedia object should be shown on the page. A false value means no and true values means yes. |
6 |
width Width of the object in pixels |
7 |
height Height of the object in pixels |
8 |
name A name used to reference the object. |
9 |
src URL of the object to be embedded. |
10 |
volume Controls volume of the sound. Can be from 0 (off) to 100 (full volume). |
Supported Video Types
可在 embed 标记中使用各种媒体类型，如 Flash 电影 (.swf)、AVI (.avi) 和 MOV (.mov) 文件类型。
You can use various media types like Flash movies (.swf), AVI’s (.avi), and MOV’s (.mov) file types inside embed tag.
-
.swf files − are the file types created by Macromedia’s Flash program.
-
.wmv files − are Microsoft’s Window’s Media Video file types.
-
.mov files − are Apple’s Quick Time Movie format.
-
.mpeg files − are movie files created by the Moving Pictures Expert Group.
<!DOCTYPE html>
<html>
<head>
<title>HTML embed Tag</title>
</head>
<body>
<embed src = "/html/yourfile.swf" width = "200" height = "200" >
<noembed><img src = "yourimage.gif" alt = "Alternative Media" ></noembed>
</embed>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Background Audio
可使用 HTML <bgsound> 标记在网页的背景中播放音轨。此标记仅受 Internet Explorer 支持，且大多数其他浏览器均忽略此标记。它会在用户首次下载并显示宿主文档时下载和播放一个音频文件。当用户刷新浏览器时，背景声音文件也会重新播放。
You can use HTML <bgsound> tag to play a soundtrack in the background of your webpage. This tag is supported by Internet Explorer only and most of the other browsers ignore this tag. It downloads and plays an audio file when the host document is first downloaded by the user and displayed. The background sound file also will replay whenever the user refreshes the browser.
Note − bgsound 标记已弃用，且应在未来的 HTML 版本中移除。因此不应使用它们，建议改为使用 HTML5 audio 标记来添加声音。但为了学习目的，本章将详细解释 bgsound 标记。
Note − The bgsound tag is deprecated and it is supposed to be removed in a future version of HTML. So they should not be used rather, it’s suggested to use HTML5 tag audio for adding sound. But still for learning purpose, this chapter will explain bgsound tag in detail.
此标记仅具有两个属性 loop 和 src。这两个属性的含义都与上文解释的相同。
This tag is having only two attributes loop and src. Both these attributes have same meaning as explained above.
以下是一个播放小型 midi 文件的简单示例 −
Here is a simple example to play a small midi file −
<!DOCTYPE html>
<html>
<head>
<title>HTML embed Tag</title>
</head>
<body>
<bgsound src = "/html/yourfile.mid">
<noembed><img src = "yourimage.gif" ></noembed>
</bgsound>
</body>
</html>这将生成空白屏幕。此标记不会显示任何组件，并保持隐藏。
This will produce the blank screen. This tag does not display any component and remains hidden.
Internet Explorer 还可以处理仅三种不同的声音格式文件：wav，适用于 PC 的原生格式；au，适用于大多数 Unix 工作站的原生格式；以及 MIDI，一种通用音乐编码方案。
Internet Explorer can also handle only three different sound format files − wav, the native format for PCs; au, the native format for most Unix workstations; and MIDI, a universal music-encoding scheme.
HTML Object tag
HTML 4 引入了 <object> 元素，它为通用对象包含提供了一种通用解决方案。借助 <object> 元素，HTML 作者可以指定用户代理对象演示所需的所有内容。
HTML 4 introduces the <object> element, which offers an all-purpose solution to generic object inclusion. The <object> element allows HTML authors to specify everything required by an object for its presentation by a user agent.
这里有一些示例 -
Here are a few examples −
Example - 1
可按如下所示将 HTML 文档嵌入到 HTML 文档本身中 −
You can embed an HTML document in an HTML document itself as follows −
<object data = "data/test.htm" type = "text/html" width = "300" height = "200">
alt : <a href = "data/test.htm">test.htm</a>
</object>如果浏览器不支持 object 标记，则 alt 特性将显示图像。
Here alt attribute will come into picture if browser does not support object tag.
Example - 2
可按如下所示将 PDF 文档嵌入到 HTML 文档中 −
You can embed a PDF document in an HTML document as follows −
<object data = "data/test.pdf" type = "application/pdf" width = "300" height = "200">
alt : <a href = "data/test.pdf">test.htm</a>
</object>Example - 3
您可通过 <param> 标记指定与文档相关的一些参数。以下是嵌入 wav 文件的一个示例：
You can specify some parameters related to the document with the <param> tag. Here is an example to embed a wav file −
<object data = "data/test.wav" type = "audio/x-wav" width = "200" height = "20">
<param name = "src" value = "data/test.wav">
<param name = "autoplay" value = "false">
<param name = "autoStart" value = "0">
alt : <a href = "data/test.wav">test.wav</a>
</object>Example - 4
您可按照以下方式添加一个 Flash 文档：
You can add a flash document as follows −
<object classid = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" id = "penguin"
codebase = "someplace/swflash.cab" width = "200" height = "300">
<param name = "movie" value = "flash/penguin.swf" />
<param name = "quality" value = "high" />
<img src = "penguin.jpg" width = "200" height = "300" alt = "Penguin" />
</object>Example - 5
您可按照以下方式向 HTML 文档中添加一个 Java 小程序：
You can add a java applet into HTML document as follows −
<object classid = "clsid:8ad9c840-044e-11d1-b3e9-00805f499d93"
width = "200" height = "200">
<param name = "code" value = "applet.class">
</object>classid 属性标识要使用的 Java Plug-in 版本。您可以使用可选的 codebase 属性指定是否及如何下载 JRE。
The classid attribute identifies which version of Java Plug-in to use. You can use the optional codebase attribute to specify if and how to download the JRE.
HTML - Marquees
HTML 股票行情是一种可滚动的文本，根据设置在您的网页上水平滚动或垂直向下滚动显示。这通过使用 HTML <marquees> 标记创建。
An HTML marquee is a scrolling piece of text displayed either horizontally across or vertically down your webpage depending on the settings. This is created by using HTML <marquees> tag.
Syntax
使用 HTML <marquee> 标记的简单语法如下：
A simple syntax to use HTML <marquee> tag is as follows −
<marquee attribute_name = "attribute_value"....more attributes>
One or more lines or text message or image
</marquee>The <marquee> Tag Attributes
以下是可与 <marquee> 标记一起使用的重要属性列表。
Following is the list of important attributes which can be used with <marquee> tag.
Sr.No |
Attribute & Description |
1 |
width This specifies the width of the marquee. This can be a value like 10 or 20% etc. |
2 |
height This specifies the height of the marquee. This can be a value like 10 or 20% etc. |
3 |
direction This specifies the direction in which marquee should scroll. This can be a value like up, down, left or right. |
4 |
behavior This specifies the type of scrolling of the marquee. This can have a value like scroll, slide and alternate. |
5 |
scrolldelay This specifies how long to delay between each jump. This will have a value like 10 etc. |
6 |
scrollamount This specifies the speed of marquee text. This can have a value like 10 etc. |
7 |
loop This specifies how many times to loop. The default value is INFINITE, which means that the marquee loops endlessly. |
8 |
bgcolor This specifies background color in terms of color name or color hex value. |
9 |
hspace This specifies horizontal space around the marquee. This can be a value like 10 or 20% etc. |
10 |
vspace This specifies vertical space around the marquee. This can be a value like 10 or 20% etc. |
下面是一些演示股票行情标记用法的示例。
Below are few examples to demonstrate the usage of marquee tag.
Examples - 1
<!DOCTYPE html>
<html>
<head>
<title>HTML marquee Tag</title>
</head>
<body>
<marquee>This is basic example of marquee</marquee>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Examples - 2
<!DOCTYPE html>
<html>
<head>
<title>HTML marquee Tag</title>
</head>
<body>
<marquee width = "50%">This example will take only 50% width</marquee>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - Header
我们已经了解到，典型的 HTML 文档将具有以下结构：
We have learnt that a typical HTML document will have following structure −
Document declaration tag
<html>
<head>
Document header related tags
</head>
<body>
Document body related tags
</body>
</html>本章节会详细讲解标题部分，标题部分由 HTML <head> 标记表示。<head> 标记是各种重要标记的容器，如 <title>、<meta>、<link>、<base>、<style>、<script> 和 <noscript> 标记。
This chapter will give a little more detail about header part which is represented by HTML <head> tag. The <head> tag is a container of various important tags like <title>, <meta>, <link>, <base>, <style>, <script>, and <noscript> tags.
The HTML <title> Tag
HTML <title> 标记用于指定 HTML 文档的标题。以下是为 HTML 文档创建标题的示例 −
The HTML <title> tag is used for specifying the title of the HTML document. Following is an example to give a title to an HTML document −
<!DOCTYPE html>
<html>
<head>
<title>HTML Title Tag Example</title>
</head>
<body>
<p>Hello, World!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The HTML <meta> Tag
HTML <meta> 标记用于提供有关 HTML 文档的元数据，其中包括有关页面过期日期、页面作者、关键字列表和页面描述等信息。
The HTML <meta> tag is used to provide metadata about the HTML document which includes information about page expiry, page author, list of keywords, page description etc.
以下是 HTML 文档中 <meta> 标记的一些重要用法 −
Following are few of the important usages of <meta> tag inside an HTML document −
<!DOCTYPE html>
<html>
<head>
<title>HTML Meta Tag Example</title>
<!-- Provide list of keywords -->
<meta name = "keywords" content = "C, C++, Java, PHP, Perl, Python">
<!-- Provide description of the page -->
<meta name = "description" content = "Simply Easy Learning by Tutorials Point">
<!-- Author information -->
<meta name = "author" content = "Tutorials Point">
<!-- Page content type -->
<meta http-equiv = "content-type" content = "text/html; charset = UTF-8">
<!-- Page refreshing delay -->
<meta http-equiv = "refresh" content = "30">
<!-- Page expiry -->
<meta http-equiv = "expires" content = "Wed, 21 June 2006 14:25:27 GMT">
<!-- Tag to tell robots not to index the content of a page -->
<meta name = "robots" content = "noindex, nofollow">
</head>
<body>
<p>Hello, World!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The HTML <base> Tag
HTML <base> 标记用于指定页面中所有相对 URL 的基础 URL，这意味着在查找给定项目时，所有其他 URL 都将与基础 URL 连接在一起。
The HTML <base> tag is used for specifying the base URL for all relative URLs in a page, which means all the other URLs will be concatenated into base URL while locating for the given item.
例如，在指定根目录 [role="bare"] [role="bare"]https://www.tutorialspoint.com/ 中给定的所有给定页面和图像都会搜索，将给定的 URL 与基础 URL 连接 −
For example, all the given pages and images will be searched after prefixing the given URLs with base URL [role="bare"]https://www.tutorialspoint.com/ directory −
<!DOCTYPE html>
<html>
<head>
<title>HTML Base Tag Example</title>
<base href = "https://www.tutorialspoint.com/" />
</head>
<body>
<img src = "/images/logo.png" alt = "Logo Image"/>
<a href = "/html/index.htm" title = "HTML Tutorial"/>HTML Tutorial</a>
</body>
</html>这会产生以下结果 −
This will produce the following result −
但是，如果您将基础 URL 更改为其他内容，例如，如果基础 URL 是 [role="bare"] [role="bare"]https://www.tutorialspoint.com/home ，则图像和其他给定的链接将变为 [role="bare"] [role="bare"]https://www.tutorialspoint.com/home/images/logo.png 和 [role="bare"] [role="bare"]https://www.tutorialspoint.com/html/index.htm
But if you change base URL to something else, for example, if base URL is [role="bare"]https://www.tutorialspoint.com/home then image and other given links will become like [role="bare"]https://www.tutorialspoint.com/home/images/logo.png and [role="bare"]https://www.tutorialspoint.com/html/index.htm
The HTML <link> Tag
HTML <link> 标记用于指定当前文档和外部资源之间的关系。以下是链接一个外部样式表文件的一个示例，该文件储存在 Web 根目录中的 css 子目录中 −
The HTML <link> tag is used to specify relationships between the current document and external resource. Following is an example to link an external style sheet file available in css sub-directory within web root −
<!DOCTYPE html>
<html>
<head>
<title>HTML link Tag Example</title>
<base href = "https://www.tutorialspoint.com/" />
<link rel = "stylesheet" type = "text/css" href = "/css/style.css">
</head>
<body>
<p>Hello, World!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
The HTML <style> Tag
HTML <style> 标记用于指定当前 HTML 文档的样式表。以下是如何在 <style> 标记中定义一些样式表规则的示例 −
The HTML <style> tag is used to specify style sheet for the current HTML document. Following is an example to define few style sheet rules inside <style> tag −
<!DOCTYPE html>
<html>
<head>
<title>HTML style Tag Example</title>
<base href = "https://www.tutorialspoint.com/" />
<style type = "text/css">
.myclass {
background-color: #aaa;
padding: 10px;
}
</style>
</head>
<body>
<p class = "myclass">Hello, World!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Note − 若需了解层叠样式表如何工作的相关信息，请查看 css 中提供的单独教程。
Note − To learn about how Cascading Style Sheet works, kindly check a separate tutorial available at css
The HTML <script> Tag
HTML <script> 标记用于包含外部脚本文件或为 HTML 文档定义内部脚本。以下是一个示例，其中我们使用 JavaScript 来定义一个简单的 JavaScript 函数 −
The HTML <script> tag is used to include either external script file or to define internal script for the HTML document. Following is an example where we are using JavaScript to define a simple JavaScript function −
<!DOCTYPE html>
<html>
<head>
<title>HTML script Tag Example</title>
<base href = "https://www.tutorialspoint.com/" />
<script type = "text/JavaScript">
function Hello() {
alert("Hello, World");
}
</script>
</head>
<body>
<input type = "button" onclick = "Hello();" name = "ok" value = "OK" />
</body>
</html>这将产生以下结果，您可以在其中尝试单击给定的按钮 −
This will produce the following result, where you can try to click on the given button −
Note − 若需了解 JavaScript 如何工作的相关信息，请查看 javascript 中提供的单独教程。
Note − To learn about how JavaScript works, kindly check a separate tutorial available at javascript
HTML - Style Sheet
层叠样式表 (CSS) 描述了文档在屏幕上、印刷品上或读音方面的呈现方式。自该联盟于 1994 年成立以来，W3C 一直积极推广在网络上使用样式表。
Cascading Style Sheets (CSS) describe how documents are presented on screens, in print, or perhaps how they are pronounced. W3C has actively promoted the use of style sheets on the Web since the consortium was founded in 1994.
级联样式表 (CSS) 提供了简便而有效的方法，可以为 HTML 标记指定各种属性。使用 CSS，可以为给定的 HTML 元素指定大量样式属性。每个属性都有一个名称和一个值，由冒号 (:) 分隔。每个属性声明都由分号 (;) 分隔。
Cascading Style Sheets (CSS) provide easy and effective alternatives to specify various attributes for the HTML tags. Using CSS, you can specify a number of style properties for a given HTML element. Each property has a name and a value, separated by a colon (:). Each property declaration is separated by a semi-colon (;).
Example
首先，让我们考虑一个 HTML 文档的示例，该示例使用 <font> 标记和关联属性来指定文本颜色和字体大小 −
First let’s consider an example of HTML document which makes use of <font> tag and associated attributes to specify text color and font size −
<!DOCTYPE html>
<html>
<head>
<title>HTML CSS</title>
</head>
<body>
<p><font color = "green" size = "5">Hello, World!</font></p>
</body>
</html>我们可以借助样式表重新编写上面的示例，如下所示 −
We can re-write above example with the help of Style Sheet as follows −
<!DOCTYPE html>
<html>
<head>
<title>HTML CSS</title>
</head>
<body>
<p style = "color:green; font-size:24px;" >Hello, World!</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
可以在 HTML 文档中通过三种方式使用 CSS −
You can use CSS in three ways in your HTML document −
-
External Style Sheet − Define style sheet rules in a separate .css file and then include that file in your HTML document using HTML <link> tag.
-
Internal Style Sheet − Define style sheet rules in header section of the HTML document using <style> tag.
-
Inline Style Sheet − Define style sheet rules directly along-with the HTML elements using style attribute.
让我们借助合适的示例依次了解所有这三种情况。
Let’s see all the three cases one by one with the help of suitable examples.
External Style Sheet
如果需要在多个页面中使用您的样式表，始终建议在单独的文件中定义通用样式表。级联样式表文件将具有 .css 扩展名，并将使用 <link> 标签包含在 HTML 文件中。
If you need to use your style sheet to various pages, then its always recommended to define a common style sheet in a separate file. A cascading style sheet file will have extension as .css and it will be included in HTML files using <link> tag.
Example
考虑我们定义一个样式表文件 style.css ，其中包含以下规则−
Consider we define a style sheet file style.css which has following rules −
.red {
color: red;
}
.thick {
font-size:20px;
}
.green {
color:green;
}在这里，我们定义了三条 CSS 规则，这些规则将适用于为 HTML 标记定义的三种不同类。我建议您不要关心这些规则是如何定义的，因为您将在学习 CSS 时学到它们。现在让我们在以下 HTML 文档中使用上述外部 CSS 文件−
Here we defined three CSS rules which will be applicable to three different classes defined for the HTML tags. I suggest you should not bother about how these rules are being defined because you will learn them while studying CSS. Now let’s make use of the above external CSS file in our following HTML document −
<!DOCTYPE html>
<html>
<head>
<title>HTML External CSS</title>
<link rel = "stylesheet" type = "text/css" href = "/html/style.css">
</head>
<body>
<p class = "red">This is red</p>
<p class = "thick">This is thick</p>
<p class = "green">This is green</p>
<p class = "thick green">This is thick and green</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Internal Style Sheet
如果您只想将样式表规则应用于单个文档，则可以使用 <style> 标签将这些规则包含在 HTML 文档的标题部分中。
If you want to apply Style Sheet rules to a single document only, then you can include those rules in header section of the HTML document using <style> tag.
在内部样式表中定义的规则会覆盖 CSS 文件中定义的规则。
Rules defined in internal style sheet overrides the rules defined in an external CSS file.
Example
让我们再次改写上面的示例，但在这里，我们将使用 <style> 标签在同一 HTML 文档中编写样式表规则−
Let’s re-write above example once again, but here we will write style sheet rules in the same HTML document using <style> tag −
<!DOCTYPE html>
<html>
<head>
<title>HTML Internal CSS</title>
<style type = "text/css">
.red {
color: red;
}
.thick{
font-size:20px;
}
.green {
color:green;
}
</style>
</head>
<body>
<p class = "red">This is red</p>
<p class = "thick">This is thick</p>
<p class = "green">This is green</p>
<p class = "thick green">This is thick and green</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Inline Style Sheet
您可以使用相关标签的 style 属性将样式表规则直接应用于任何 HTML 元素。仅当您有兴趣在任何 HTML 元素中进行特定更改时才应执行此操作。
You can apply style sheet rules directly to any HTML element using style attribute of the relevant tag. This should be done only when you are interested to make a particular change in any HTML element only.
与元素同级定义的规则将覆盖外部 CSS 文件中定义的规则以及 <style> 元素中定义的规则。
Rules defined inline with the element overrides the rules defined in an external CSS file as well as the rules defined in <style> element.
Example
让我们再次改写上面的示例，但在这里，我们将使用这些元素的 style 属性与 HTML 元素一起编写样式表规则。
Let’s re-write above example once again, but here we will write style sheet rules along with the HTML elements using style attribute of those elements.
<!DOCTYPE html>
<html>
<head>
<title>HTML Inline CSS</title>
</head>
<body>
<p style = "color:red;">This is red</p>
<p style = "font-size:20px;">This is thick</p>
<p style = "color:green;">This is green</p>
<p style = "color:green;font-size:20px;">This is thick and green</p>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML - JavaScript
script 是一小段程序，可以为您的网站添加交互性。例如，脚本可以生成一个弹出警告框消息，或提供下拉菜单。此脚本可以使用 JavaScript 或 VBScript 编写。
A script is a small piece of program that can add interactivity to your website. For example, a script could generate a pop-up alert box message, or provide a dropdown menu. This script could be written using JavaScript or VBScript.
您可以使用任何脚本语言编写各种小函数（称为事件处理程序），然后可以使用 HTML 属性触发这些函数。
You can write various small functions, called event handlers using any of the scripting language and then you can trigger those functions using HTML attributes.
如今，大多数 Web 开发人员仅使用 JavaScript 及其关联框架，各种主流浏览器甚至都不支持 VBScript。
Now-a-days, only JavaScript and associated frameworks are being used by most of the web developers, VBScript is not even supported by various major browsers.
您可以将 JavaScript 代码保存在一个单独的文件中，然后在需要时包含它，也可以在 HTML 文档本身中定义功能。让我们逐一了解这两个案例及其合适的示例。
You can keep JavaScript code in a separate file and then include it wherever it’s needed, or you can define functionality inside HTML document itself. Let’s see both the cases one by one with suitable examples.
External JavaScript
如果您要定义将在多个 HTML 文档中使用的功能，则最好将该功能保留在单独的 JavaScript 文件中，然后将该文件包含在您的 HTML 文档中。JavaScript 文件将具有 .js 扩展名，并将使用 <script> 标签包含在 HTML 文件中。
If you are going to define a functionality which will be used in various HTML documents then it’s better to keep that functionality in a separate JavaScript file and then include that file in your HTML documents. A JavaScript file will have extension as .js and it will be included in HTML files using <script> tag.
Example
考虑我们在 script.js 中使用 JavaScript 定义一个小的函数，其中包含以下代码−
Consider we define a small function using JavaScript in script.js which has following code −
function Hello() {
alert("Hello, World");
}现在让我们在以下 HTML 文档中使用上述外部 JavaScript 文件−
Now let’s make use of the above external JavaScript file in our following HTML document −
<!DOCTYPE html>
<html>
<head>
<title>Javascript External Script</title>
<script src = "/html/script.js" type = "text/javascript"/></script>
</head>
<body>
<input type = "button" onclick = "Hello();" name = "ok" value = "Click Me" />
</body>
</html>这将产生以下结果，您可以在其中尝试单击给定的按钮 −
This will produce the following result, where you can try to click on the given button −
Internal Script
您可以直接在 HTML 文档中编写脚本代码。通常来说，我们使用 <script> 标记将脚本代码放在文档头中，但除此之外没有限制，您可以将源代码放置在文档的任何地方，但前提是需要放在 <script> 标记中。
You can write your script code directly into your HTML document. Usually we keep script code in header of the document using <script> tag, otherwise there is no restriction and you can put your source code anywhere in the document but inside <script> tag.
Example
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Internal Script</title>
<base href = "https://www.tutorialspoint.com/" />
<script type = "text/JavaScript">
function Hello() {
alert("Hello, World");
}
</script>
</head>
<body>
<input type = "button" onclick = "Hello();" name = "ok" value = "Click Me" />
</body>
</html>这将产生以下结果，您可以在其中尝试单击给定的按钮 −
This will produce the following result, where you can try to click on the given button −
Event Handlers
事件处理程序只不过是针对任何鼠标或键盘事件调用已定义函数。您可以在自己编写的事件处理程序中定义业务逻辑，代码行数可以从一行到数千行不等。
Event handlers are nothing but simply defined functions which can be called against any mouse or keyboard event. You can define your business logic inside your event handler which can vary from a single to 1000s of line code.
以下示例介绍如何编写事件处理程序。让我们在文档头中编写一个简单的函数 EventHandler()。当任何用户将鼠标移动到一段文字时，将调用此函数。
Following example explains how to write an event handler. Let’s write one simple function EventHandler() in the header of the document. We will call this function when any user brings mouse over a paragraph.
<!DOCTYPE html>
<html>
<head>
<title>Event Handlers Example</title>
<base href = "https://www.tutorialspoint.com/" />
<script type = "text/JavaScript">
function EventHandler() {
alert("I'm event handler!!");
}
</script>
</head>
<body>
<p onmouseover = "EventHandler();">Bring your mouse here to see an alert</p>
</body>
</html>现在，这将产生以下结果。将鼠标移到此行上并查看结果：
Now This will produce the following result. Bring your mouse over this line and see the result −
Hide Scripts from Older Browsers
虽然如今大多数（如果不是全部）浏览器都支持 JavaScript，但仍有一些较旧的浏览器不支持。如果浏览器不支持 JavaScript，它将向用户显示代码，而不是运行您的脚本。为了防止这种情况，您可以按照以下方式在脚本周围放置 HTML 注释。
Although most (if not all) browsers these days support JavaScript, but still some older browsers don’t. If a browser doesn’t support JavaScript, instead of running your script, it would display the code to the user. To prevent this, you can simply place HTML comments around the script as shown below.
JavaScript Example:
<script type = "text/JavaScript">
<!--
document.write("Hello JavaScript!");
//-->
</script>
VBScript Example:
<script type = "text/vbscript">
<!--
document.write("Hello VBScript!")
'-->
</script>The <noscript> Element
您还可以向浏览器不支持脚本或已禁用脚本选项的浏览器用户提供其他信息。您可以使用 <noscript> 标记来实现此目的。
You can also provide alternative info to the users whose browsers don’t support scripts and for those users who have disabled script option their browsers. You can do this using the <noscript> tag.
JavaScript Example:
<script type = "text/JavaScript">
<!--
document.write("Hello JavaScript!");
//-->
</script>
<noscript>Your browser does not support JavaScript!</noscript>
VBScript Example:
<script type = "text/vbscript">
<!--
document.write("Hello VBScript!")
'-->
</script>
<noscript>Your browser does not support VBScript!</noscript>Default Scripting Language
您可能会遇到包含多个脚本文件并最终使用多个 <script> 标记的情况。您可以为所有脚本标记指定默认脚本语言。这样可以省去每次在页面中使用脚本标记时指定语言的麻烦。以下是示例：
There may be a situation when you will include multiple script files and ultimately using multiple <script> tags. You can specify a default scripting language for all your script tags. This saves you from specifying the language every time you use a script tag within the page. Below is the example −
<meta http-equiv = "Content-Script-Type" content = "text/JavaScript" />请注意，您仍然可以通过在脚本标记中指定语言来覆盖默认设置。
Note that you can still override the default by specifying a language within the script tag.
HTML - Layouts
网页布局非常重要，它可以为您的网站提供更好的外观。设计一个美观又实用的网站布局需要花费大量时间。
A webpage layout is very important to give better look to your website. It takes considerable time to design a website’s layout with great look and feel.
如今，所有现代网站都使用基于 CSS 和 JavaScript 的框架来设计响应式且动态的网站，但您可以使用简单的 HTML 表格或分隔式标记结合其他格式化标记来创建良好的布局。本章将为您提供一些示例，说明如何使用纯 HTML 及其属性为您的网页创建简单但实用的布局。
Now-a-days, all modern websites are using CSS and JavaScript based framework to come up with responsive and dynamic websites but you can create a good layout using simple HTML tables or division tags in combination with other formatting tags. This chapter will give you few examples on how to create a simple but working layout for your webpage using pure HTML and its attributes.
HTML Layout - Using Tables
创建布局的最简单且最流行的方法是使用 HTML <table> 标记。这些表格按列和行排列，因此您可以根据需要以任何方式使用这些行和列。
The simplest and most popular way of creating layouts is using HTML <table> tag. These tables are arranged in columns and rows, so you can utilize these rows and columns in whatever way you like.
Example
例如，以下 HTML 布局示例是使用具有 3 行和 2 列的表格实现的，但页眉和页脚列使用 colspan 属性跨越这两列：
For example, the following HTML layout example is achieved using a table with 3 rows and 2 columns but the header and footer column spans both columns using the colspan attribute −
<!DOCTYPE html>
<html>
<head>
<title>HTML Layout using Tables</title>
</head>
<body>
<table width = "100%" border = "0">
<tr>
<td colspan = "2" bgcolor = "#b5dcb3">
<h1>This is Web Page Main title</h1>
</td>
</tr>
<tr valign = "top">
<td bgcolor = "#aaa" width = "50">
<b>Main Menu</b><br />
HTML<br />
PHP<br />
PERL...
</td>
<td bgcolor = "#eee" width = "100" height = "200">
Technical and Managerial Tutorials
</td>
</tr>
<tr>
<td colspan = "2" bgcolor = "#b5dcb3">
<center>
Copyright © 2007 Tutorialspoint.com
</center>
</td>
</tr>
</table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
Multiple Columns Layout - Using Tables
您可以设计您的网页，将您的网络内容置于多页中。您可以将您的内容保持在中间列，并可以使用左列作为菜单，右列可以用来放置广告或其他内容。此布局将与我们在网站 tutorialspoint.com 上的布局非常相似。
You can design your webpage to put your web content in multiple pages. You can keep your content in middle column and you can use left column to use menu and right column can be used to put advertisement or some other stuff. This layout will be very similar to what we have at our website tutorialspoint.com.
Example
以下是创建三列布局的示例：
Here is an example to create three column layout −
<!DOCTYPE html>
<html>
<head>
<title>Three Column HTML Layout</title>
</head>
<body>
<table width = "100%" border = "0">
<tr valign = "top">
<td bgcolor = "#aaa" width = "20%">
<b>Main Menu</b><br />
HTML<br />
PHP<br />
PERL...
</td>
<td bgcolor = "#b5dcb3" height = "200" width = "60%">
Technical and Managerial Tutorials
</td>
<td bgcolor = "#aaa" width = "20%">
<b>Right Menu</b><br />
HTML<br />
PHP<br />
PERL...
</td>
</tr>
<table>
</body>
</html>这会产生以下结果 −
This will produce the following result −
HTML Layouts - Using DIV, SPAN
<div> 元素是一个块级元素，用于对 HTML 元素进行分组。虽然 <div> 标记是一个块级元素，但 HTML <span> 元素用于在行内级对元素进行分组。
The <div> element is a block level element used for grouping HTML elements. While the <div> tag is a block-level element, the HTML <span> element is used for grouping elements at an inline level.
尽管我们可以使用 HTML 表格实现非常漂亮的布局，但表格实际上并不是作为一种布局工具设计的。表格更适合于显示表格数据。
Although we can achieve pretty nice layouts with HTML tables, but tables weren’t really designed as a layout tool. Tables are more suited to presenting tabular data.
Note - 此示例使用层叠样式表 (CSS)，因此在理解此示例之前，您需要更好地理解 CSS 的工作原理。
Note − This example makes use of Cascading Style Sheet (CSS), so before understanding this example you need to have a better understanding on how CSS works.
Example
在此，我们将尝试使用 <div> 标记和 CSS 实现相同的结果，无论您在前面的示例中使用 <table> 标记实现什么。
Here we will try to achieve same result using <div> tag along with CSS, whatever you have achieved using <table> tag in previous example.
<!DOCTYPE html>
<html>
<head>
<title>HTML Layouts using DIV, SPAN</title>
</head>
<body>
<div style = "width:100%">
<div style = "background-color:#b5dcb3; width:100%">
<h1>This is Web Page Main title</h1>
</div>
<div style = "background-color:#aaa; height:200px; width:100px; float:left;">
<div><b>Main Menu</b></div>
HTML<br />
PHP<br />
PERL...
</div>
<div style = "background-color:#eee; height:200px; width:350px; float:left;" >
<p>Technical and Managerial Tutorials</p>
</div>
<div style = "background-color:#aaa; height:200px; width:100px; float:right;">
<div><b>Right Menu</b></div>
HTML<br />
PHP<br />
PERL...
</div>
<div style = "background-color:#b5dcb3; clear:both">
<center>
Copyright © 2007 Tutorialspoint.com
</center>
</div>
</div>
</body>
</html>这会产生以下结果 −
This will produce the following result −
您可以使用 DIV、SPAN 和 CSS 创建更好的布局。有关 CSS 的更多信息，请参阅 CSS 教程。
You can create better layout using DIV, SPAN along with CSS. For more information on CSS, please refer to CSS Tutorial.