When using an asynchronous request, it is sometimes necessary to return the result of an asynchronous request to another JS function, in which case an asynchronous request returns the result of the request, which is where the JS function has performed the subsequent operation, that is, the return has been executed, which will result in a null character return.
Summary: To handle the results returned by a send request after using an AJAX request, it is best to use a synchronization request.
For example, the following example shows an incorrect return result because the Ajax asynchronous request has not been completed and the function has already executed return.
function fn () {
var result = "";
$.ajax ({
URL: ' Your URL ',
Data:{name:value},
Cache:false,
Async:true,
Type: "POST",
Success:function (data) {
Do something ....
result = ....
}
Processing of data returned in Ajax can also be an error
return result;
}
1 Asynchronous Request mode:
$.ajax ({
URL: ' Your URL ',
Data:{name:value},
Cache:false,
Async:true,
Type: "POST",
DataType: ' json/xml/html ',
Success:function (Result) {
Do something ....
}
});
2 Synchronous Request Mode
$.ajax ({
URL: ' Your URL ',
Data:{name:value},
Cache:false,
Async:false,
Type: "POST",
DataType: ' json/xml/html ',
Success:function (Result) {
Do something ....
}
});
Synchronous and asynchronous processing methods in JS
