当远程文件修改后，装入修改后的远程文件页请内容到DOM元素.

返回值:jQuery

参数:

• url (String): 装入的HTML文件url地址
• params (Map): 可选）发送到服务端的键／值对参数。
• callback (Function): 可选） 当数据装入完成时执行的函数.

示例:

$("#feeds").loadIfModified("feeds.html");

HTML 代码:

<div id="feeds"></div>

结果:

<div id="feeds"><b>45</b> feeds found.</div>

Load HTML from a remote file and inject it into the DOM, only if it's been modified by the server.

Return value: jQuery
Parameters:

• url (String): The URL of the HTML file to load.
• params (Map): (optional) Key/value pairs that will be sent to the server.
• callback (Function): (optional) A function to be executed whenever the data is loaded (parameters: responseText, status and response itself).

Example:

 $("#feeds").loadIfModified("feeds.html");  

 <div id="feeds"></div>  

 <div id="feeds"><b>45</b> feeds found.</div>