Jquery AJAX with ASP.NET WebMethod Returning Entire Page

I'm doing some simple tests (in preparation for a larger project) to call an ASP.NET WebMethod using JQuery AJAX. In my example, my WebMethod returns a simple string. However, when I attempt to call it using JQuery, I get the entire HTML page content returned instead of just my string. What am I missing?

Client Side :

$(document).ready(function ready() {

        $("#MyButton").click(function clicked(e) {

            $.post("Default.aspx/TestMethod",

                {name:"Bob"},

                function(msg) {

                    alert("Data Recieved: " + msg);

                },

                "html"

            );

        });

    });

Server Side:

using System;

using System.Web.Services;



namespace JqueryAjaxText

{

    public partial class _Default : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {



        }



        [WebMethod]

        public static string TestMethod(string name)

        {

            return "The value submitted was " + name;

        }

    }

}

Source: Tips4all, CCNA FINAL EXAM