Question

I have defined a JavaScript function

function a()

 {
    var data = 'some data';
    $.getJSON(networkController,data,function(r) {
            $.each(r, function(a)
            {
                alert(r[a].networkAccessToken);
        });
   });
}

It works fine but When I do it as:

 function a()

 {
    var data = 'some data';
    $.getJSON(networkController,data,function(r) {
            $.each(r, function(a)
            {
                return r[a].networkAccessToken;
        });
  });
 }
var c = a();
alert(c);

Alert is undefined…..

Answer 1

It’s important to realise that your AJAX call is non-blocking. This means that it returns before a response is received from the server. (The first “A” stands for “Asynchronous”!)

The most common way to handle this is to use a callback:

 function a(callback) {
    var data = 'some data';
    $.getJSON(networkController,data,function(r) {
        $.each(r, function(a) {
            callback(r[a].networkAccessToken);
        });
    });
 }

 a(function(c) {
   alert(c);
 });