Javascript 简明教程

JavaScript - Multimedia

JavaScript` navigator 对象包括一个名为 plugins `的子对象。这个对象是一个数组，其中有一个浏览器上已安装的每个插件的条目。`navigator.plugins`对象仅受Netscape、Firefox和Mozilla支持。

The JavaScript navigator object includes a child object called plugins. This object is an array, with one entry for each plug-in installed on the browser. The navigator.plugins object is supported only by Netscape, Firefox, and Mozilla only.

Example

下面是一个示例，它展示了如何列出你的浏览器中安装的所有插件：

Here is an example that shows how to list down all the plug-on installed in your browser −

<html>
   <head>
      <title>List of Plug-Ins</title>
   </head>

   <body>
      <table border = "1">
         <tr>
            <th>Plug-in Name</th>
            <th>Filename</th>
            <th>Description</th>
         </tr>

         <script language = "JavaScript" type = "text/javascript">
            for (i = 0; i<navigator.plugins.length; i++) {
               document.write("<tr><td>");
               document.write(navigator.plugins[i].name);
               document.write("</td><td>");
               document.write(navigator.plugins[i].filename);
               document.write("</td><td>");
               document.write(navigator.plugins[i].description);
               document.write("</td></tr>");
            }
         </script>
      </table>
   </body>
</html>

Checking for Plug-Ins

每个插件在数组中都有一个条目。每个条目有以下的属性：

Each plug-in has an entry in the array. Each entry has the following properties −

  1. name − is the name of the plug-in.

  2. filename − is the executable file that was loaded to install the plug-in.

  3. description − is a description of the plug-in, supplied by the developer.

  4. mimeTypes − is an array with one entry for each MIME type supported by the plug-in.

你可以在脚本中使用这些属性来找出已安装的插件，然后使用JavaScript播放适当的多媒体文件。看看下面的示例。

You can use these properties in a script to find out the installed plug-ins, and then using JavaScript, you can play appropriate multimedia file. Take a look at the following example.

<html>
   <head>
      <title>Using Plug-Ins</title>
   </head>

   <body>
      <script language = "JavaScript" type = "text/javascript">
         media = navigator.mimeTypes["video/quicktime"];

         if (media) {
            document.write("<embed src = 'quick.mov' height = 100 width = 100>");
         } else {
            document.write("<img src = 'quick.gif' height = 100 width = 100>");
         }
      </script>
   </body>
</html>

` NOTE ` - 我们在这里使用HTML`<embed>`标签嵌入多媒体文件。

NOTE − Here we are using HTML <embed> tag to embed a multimedia file.

Controlling Multimedia

让我们举一个在几乎所有浏览器中都适用的真实示例：

Let us take one real example which works in almost all the browsers −

<html>
   <head>
      <title>Using Embeded Object</title>

      <script type = "text/javascript">
         function play() {
            if (!document.demo.IsPlaying()) {
               document.demo.Play();
            }
         }
         function stop() {
            if (document.demo.IsPlaying()) {
               document.demo.StopPlay();
            }
         }
         function rewind() {
            if (document.demo.IsPlaying()) {
               document.demo.StopPlay();
            }
            document.demo.Rewind();
         }
      </script>
   </head>

   <body>
      <embed id = "demo" name = "demo"
         src = "http://www.amrood.com/games/kumite.swf"
         width = "318" height = "300" play = "false" loop = "false"
         pluginspage = "http://www.macromedia.com/go/getflashplayer"
         swliveconnect = "true">

      <form name = "form" id = "form" action = "#" method = "get">
         <input type = "button" value = "Start" onclick = "play();" />
         <input type = "button" value = "Stop" onclick = "stop();" />
         <input type = "button" value = "Rewind" onclick = "rewind();" />
      </form>
   </body>
</html>