AJAX实际运行当中,对于访问XMLHttpRequest(XHR)时并不是一次完成的,而是分别经历了多种状态后取得的结果,对于这种状态在AJAX中共有5种,分别是。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. 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, 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对于上面的状态,其中“0”状态是在定义后自动具有的状态值,而对于成功访问的状态(得到信息)我们大多数采用“4”进行判断。
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.
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,
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对于上面的状态,其中“0”状态是在定义后自动具有的状态值,而对于成功访问的状态(得到信息)我们大多数采用“4”进行判断。
或者把下一步方法写到回调函数里