Reuse ASPX page to generate JSON representation object

My Criteria:

a. reuse aspx page for a javascript to call one of my method in aspx.cs
b. return as JSON representation string

Here goes my code:
ASPX:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test1.aspx.cs" Inherits="Test" %>

//include this in your header 
<script src="jquery.min.js" type="text/javascript" />

<div id="test"%> </div%>

<script>
$(document).ready(function () {
$.ajax({
                type: "POST",
                url: "Test1.aspx/GetJson",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (data) {
                    $("#test").html(eval ( data.d ) );
 //if server return as string, we need to use Eval to convert to object
               
                }

            })


        });
       </script>

Code Behind: ASPX.CS
//Make sure to include System.Web.Services in the project


using System;
using System.Web.Services;


namespace Test1
{
    public partial class test
    {
        protected void Page_Load(object sender, EventArgs e)
        {
        }

         [WebMethod]
        public static string GetJson() {
               var returnString = new {Country="Singapore", Sales=200};
               return returnString;
     

        }
    }
}

Hope this help those who encounter my scenario.