javascript - xhr.readystate===4是什么意思

Question

AJAX调用在xhr.readystate===4之后完成是否正确？
Here它说状态是 complete。那么这个complete是什么意思呢？

Answer 1

Ajax http 请求有 5 种状态作为您的引用文档:

0   UNSENT  open() has not been called yet.
1   OPENED  send() has been called.
2   HEADERS_RECEIVED    send() has been called, and headers and status are available.
3   LOADING Downloading; responseText holds partial data.
4   DONE    The operation is complete.

状态4表示请求已发送，服务器已返回响应完毕，浏览器已完成下载响应内容。所以，说 AJAX 调用已经完成是正确的。