Implement Script Callback Framework in ASP.NET 1.x

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace ScriptCallbackFramework
{
	/// <summary>
	/// Implement the in IClientCallbackEventHandler Page Control
	/// </summary>
	public class index : PageTemplate, IClientCallbackEventHandler
	{
		#region Member Vars
		protected System.Web.UI.HtmlControls.HtmlInputButton IncreaseButton;
		protected System.Web.UI.HtmlControls.HtmlInputText txtValue;
		protected ScriptCallbackFramework.AgeCalculator AgeCalculator1;
		protected System.Web.UI.HtmlControls.HtmlForm Form1;
		#endregion
		
		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion
		
		#region Page_Load
		private void Page_Load(object sender, System.EventArgs e)
		{
			if (!Page.IsPostBack)
			{
				//	Callback synchronously
				IncreaseButton.Attributes["onclick"] = GetSyncCallbackEventReference
					(
						Form1,
						String.Format("document.getElementById('{0}').value", txtValue.UniqueID),
						"IncreaseValueHandler",
						String.Format("document.getElementById('{0}')", txtValue.UniqueID),
						null
					);
			}
		}
		#endregion

		#region IClientCallbackEventHandler Members

		public string RaiseClientCallbackEvent(string eventArgument)
		{
			if (eventArgument == null || eventArgument == String.Empty)
				return "1";
			return Convert.ToString(Convert.ToInt32(eventArgument) + 1);
		}
		
		#endregion
	}
}