Jquery Ajax Call, doesn't call Success or Error [duplicate]

Answer 1

change your code to:

function ChangePurpose(Vid, PurId) {
    var Success = false;
    $.ajax({
        type: "POST",
        url: "CHService.asmx/SavePurpose",
        dataType: "text",
        async: false,
        data: JSON.stringify({ Vid: Vid, PurpId: PurId }),
        contentType: "application/json; charset=utf-8",
        success: function (data) {
            Success = true;
        },
        error: function (textStatus, errorThrown) {
            Success = false;
        }
    });
    //done after here
    return Success;
} 

You can only return the values from a synchronous function. Otherwise you will have to make a callback.

So I just added async:false, to your ajax call

Update:

jquery ajax calls are asynchronous by default. So success & error functions will be called when the ajax load is complete. But your return statement will be executed just after the ajax call is started.

A better approach will be:

     // callbackfn is the pointer to any function that needs to be called
     function ChangePurpose(Vid, PurId, callbackfn) {
        var Success = false;
        $.ajax({
            type: "POST",
            url: "CHService.asmx/SavePurpose",
            dataType: "text",
            data: JSON.stringify({ Vid: Vid, PurpId: PurId }),
            contentType: "application/json; charset=utf-8",
            success: function (data) {
                callbackfn(data)
            },
            error: function (textStatus, errorThrown) {
                callbackfn("Error getting the data")
            }
        });
     } 

     function Callback(data)
     {
        alert(data);
     }

and call the ajax as:

 // Callback is the callback-function that needs to be called when asynchronous call is complete
 ChangePurpose(Vid, PurId, Callback);

Answer 2

Try to encapsulate the ajax call into a function and set the async option to false. Note that this option is deprecated since jQuery 1.8.

function foo() {
    var myajax = $.ajax({
        type: "POST",
        url: "CHService.asmx/SavePurpose",
        dataType: "text",
        data: JSON.stringify({ Vid: Vid, PurpId: PurId }),
        contentType: "application/json; charset=utf-8",
        async: false, //add this
    });
    return myajax.responseText;
}

You can do this also:

$.ajax({
    type: "POST",
    url: "CHService.asmx/SavePurpose",
    dataType: "text",
    data: JSON.stringify({ Vid: Vid, PurpId: PurId }),
    contentType: "application/json; charset=utf-8",
    async: false, //add this
}).done(function ( data ) {
        Success = true;
}).fail(function ( data ) {
       Success = false;
});

You can read more about the jqXHR jQuery Object