Data Controls :: Data Retrieve From Ajax On Button Click

I want to retrieve data from database every time 10 But When i Fire Ajax then Function Not Call . all Design Are Come In Response.

My Ajax Code In Default Page Where Add More Button .

$.ajax({
url: "scroll.aspx/GetDataFromServer",
data: "{}",
type: "POST",
success: function (data) {
alert(data);

[Code] ...

Something should be wrong alert comes. My scroll page function ..

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Security;

[Code] ....