XMLHttpRequest对象的open()和send()方法有什么区别?
问题描述：
XMLHttpRequest 对象:
打开(< method>，< url>，< is async>))发送(< request_data>)
- 这些有何不同?为什么我们都需要同时实现ajax?
- 此外，
< request_data>是否可以通过这两种方法传递?
- How are these different and why do we need both to implement ajax?
- Also, can the
<request_data>be passed through both the methods ?
答
open()无法打开连接；它仅配置请求，但网络活动仅以send()的调用开始
open() does not open the connection; it only configures the request, but the network activity only starts with the call of send ()