用document.onreadystatechange的方法来监听状态改变， 然后用document.readyState == “complete”判断是否加载完成 [b]代码如下[/b]： [b]页面加载readyState的五种状态[/b] 原文如下: 0: (Uninitialized) the send( ) method has not yet been invoked. 1: (Loading) the send( ) method has been invoked, request in progress. 2: (Loaded) the send( ) method has completed, entire response received. 3: (Interactive) the response is being parsed. 4: (Completed) the response has been parsed, is ready for harvesting. [b]翻译成中文为[/b]: 0 － （未初始化）还没有调用send()方法 1 － （载入）已调用send()方法，正在发送请求 2 － （载入完成）send()方法执行完成，已经接收到全部响应内容 3 － （交互）正在解析响应内容 4 － （完成）响应内容解析完成，可以在客户端调用了