Jquery ajax success function returns null?

[eluser]Cristian Gilè[/eluser]

Code:

function getRecordspage() {
        $.ajax({
            type: "POST",
            url:"http://localhost/codeigniter_cup_myth/index.php/adminController/mainAccount",
            global:false,
            dataType: "json",
            success: function(result) {
               var obj = eval(result);
               alert(obj.account + obj.comment);
            }
        });

Cristian Gilè