Javascrip: ajax
- synchronous 绑定事件需在send前, 否则 事件绑定无效
- readyState
同步:
异步:
- 查看各readyState阶段responseText
- status
正常响应:
404:
- 兼容写法
简洁写法
- 发送query_string参数
- application/x-www-form-urlencoded
- application/json
>
"display: none;">username&password wrong
username: "text" name="username" autocomplete="off">
password: "text" name="password" autocomplete="off">