Dom 简明教程
XML DOM - Get Node
在本章中，我们将研究如何获取 XML DOM 对象的节点值。XML 文档具有一个信息单元层次结构，称为节点。节点对象具有属性 nodeValue，它返回元素的值。
In this chapter, we will study about how to get the node value of a XML DOM object. XML documents have a hierarchy of informational units called nodes. Node object has a property nodeValue, which returns the value of the element.
在以下部分中，我们将讨论：
In the following sections, we will discuss −
-
Getting node value of an element
-
Getting attribute value of a node
所有以下示例中使用的 node.xml 如下：
The node.xml used in all the following examples is as below −
<Company>
<Employee category = "Technical">
<FirstName>Tanmay</FirstName>
<LastName>Patil</LastName>
<ContactNo>1234567890</ContactNo>
<Email>tanmaypatil@xyz.com</Email>
</Employee>
<Employee category = "Non-Technical">
<FirstName>Taniya</FirstName>
<LastName>Mishra</LastName>
<ContactNo>1234667898</ContactNo>
<Email>taniyamishra@xyz.com</Email>
</Employee>
<Employee category = "Management">
<FirstName>Tanisha</FirstName>
<LastName>Sharma</LastName>
<ContactNo>1234562350</ContactNo>
<Email>tanishasharma@xyz.com</Email>
</Employee>
</Company>Get Node Value
getElementsByTagName() 方法按文档顺序返回带给定标签名称的所有元素的 NodeList。
The method getElementsByTagName() returns a NodeList of all the Elements in document order with a given tag name.
Example
以下示例 (getnode_example.htm) 将 XML 文档 ( node.xml ) 解析为 XML DOM 对象，并提取子节点 Firstname（索引为 0） 的节点值：
The following example (getnode_example.htm) parses an XML document (node.xml) into an XML DOM object and extracts the node value of the child node Firstname (index at 0) −
<!DOCTYPE html>
<html>
<body>
<script>
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else{
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","/dom/node.xml",false);
xmlhttp.send();
xmlDoc = xmlhttp.responseXML;
x = xmlDoc.getElementsByTagName('FirstName')[0]
y = x.childNodes[0];
document.write(y.nodeValue);
</script>
</body>
</html>Get Attribute Value
属性是 XML 节点元素的一部分。节点元素可以具有多个唯一属性。属性提供有关 XML 节点元素的更多信息。更准确地说，它们定义了节点元素的属性。XML 属性始终是一对名称 - 值。此属性的值称为属性节点。
Attributes are part of the XML node elements. A node element can have multiple unique attributes. Attribute gives more information about XML node elements. To be more precise, they define properties of the node elements. An XML attribute is always a name-value pair. This value of the attribute is called the attribute node.
getAttribute() 方法按元素名称检索属性值。
The getAttribute() method retrieves an attribute value by element name.
Example
以下示例 (get_attribute_example.htm) 将 XML 文档 ( node.xml ) 解析为 XML DOM 对象，并提取类别 Employee（索引为 2） 的属性值：
The following example (get_attribute_example.htm) parses an XML document (node.xml) into an XML DOM object and extracts the attribute value of the category Employee (index at 2) −
<!DOCTYPE html>
<html>
<body>
<script>
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","/dom/node.xml",false);
xmlhttp.send();
xmlDoc = xmlhttp.responseXML;
x = xmlDoc.getElementsByTagName('Employee')[2];
document.write(x.getAttribute('category'));
</script>
</body>
</html>