How Ajax obtains data after successful return data is declared as a global variable

var result= ""; $.ajax ({    "post",    ".. /reportrule/main.do?method=selectreporttoadd ",    data:{},    function(msg) {        = msg;          alert (result); \ \ have data    }}); Alert (result)\ \ No data 

Reason:

Ajax is an asynchronous request, that is, JavaScript is non-blocking, and the alert naming may be executed after $.ajax has not run, although there is no data for the second alert

Workaround:
Set Ajax as the synchronization request and set the Async property of $.ajax to False.

How Ajax obtains data after successful return data is declared as a global variable