readyState
值的完整列表为:
State Description
0 The request is not initialized
1 The request has been set up
2 The request has been sent
3 The request is in process
4 The request is complete
实际上,除了4之外,几乎几乎不使用它们中的任何一个。
_些XMLHttpRequest实现可能使您在responseText
when中看到部分接收到的响应readyState==3
,但这不是普遍支持的,因此不应依赖。