A brief analysis of the reasons why global variables cannot be assigned values ​​in jquery ajax asynchronous calling methods and their solutions_jquery

When calling a jquery ajax method, we sometimes need the method to return a value or assign a value to a global variable, but we find that the value we want is not obtained after the program is executed. This is very likely It’s because you are using ajax’s asynchronous call async:true (default), such as:

Copy code The 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 above method is a synchronous call of ajax. Only after the data value is obtained and assigned to the result, the result will be returned to complete the call of the method. If set to async:true,
will return the result before getting the data value.

Another solution is to write your code directly into the success method. (Depending on your business, not everything can be written directly into success).

Note: If set to async: false, the advantages of ajax asynchronousness will be lost.