Jquery Ajax Sucess data is 'Undefined'

Jquery Ajax Sucess data is 'Undefined'

Hi all,

I am using this simple code to make ajax request. The problem is data is returning 'undefined'. The data that is returning from the asp.net generic handler is "Hello World". I don't know why and from last two days I am wondering on the web.. Earlier it was working fine. I have done all the possible solutions to get around this. if anybody can help me ......  please look into the issue...
Thanks......

$(function () {
            $.ajax({
                url: "http://localhost:51721/handler1.ashx",
                async: true,
                success: function (data) {
                    alert(data);
                },
                error: function (data) {
                    alert("Problem exporting data!");
                }
            });
        });