ajaxStart (Global Event) This event is broadcast if an Ajax request is started and no other Ajax requests are currently running.
beforeSend (Local Event) This event, which is triggered before an Ajax request is started, allows you to modify the XMLHttpRequest object (setting additional headers, if need be.)
ajaxSend (Global Event) This global event is also triggered before the request is run.
success (Local Event) This event is only called if the request was successful (no errors from the server, no errors with the data).
ajaxSuccess (Global Event) This event is also only called if the request was successful.
error (Local Event) This event is only called if an error occurred with the request (you can never have both an error and a success callback with a request).
ajaxError (Global Event) This global event behaves the same as the local error event.
complete (Local Event) This event is called regardless of if the request was successful, or not. You will always receive a complete callback, even for synchronous requests.
ajaxComplete (Global Event) This event behaves the same as the complete event and will be triggered every time an Ajax request finishes.
ajaxStop (Global Event) This global event is triggered if there are no more Ajax requests being processed.
注意: 如果你指定了 dataType 选项,请确保服务器返回正确的 MIME 信息,(如 xml 返回 "text/xml")。错误的 MIME 类型可能导致不可预知的错误。见 Specifying the Data Type for AJAX Requests 。 当设置 datatype 类型为 'script' 的时候,所有的远程(不在同一个域中)POST请求都回转换为GET方式。