Reasons why global variables cannot be assigned in jquery ajax asynchronous call methods and Solutions

When calling a jquery ajax method, we sometimes need this method to return a value or assign a value to a global variable. However, we find that the program has not obtained the value we want after execution, at this time, it is very likely that you use ajax to asynchronously call async: true (default), such:
Copy codeThe Code is as follows:
Function ManageCommentText (text ){
Var result = text;
$. Ajax ({
Data: "get ",
Url: "GetComments. aspx ",
Data: "type = getText & commentText =" + text,
Cache: false,
Async: false,
Success: function (data ){
Result = data;
}
})
Return result;

The preceding method is a synchronous call of ajax. A result is returned to call the method only after the data value is obtained and assigned to the result. If set to async: true,
The result is returned before the data value is obtained.

Another solution is to write your code directly to the success method. (Not all of your business can be directly written into success ).

NOTE: If it is set to async: false, the advantages of ajax Asynchronization will be lost.