Server side Message box when Ajax is using

How to show server side messagebox when ajax is using,Messagebox in Ajax
When Ajax Content is using ,it is too tough to show a javascript alert message box from the server side in the webpage.Following function to show message box in Ajax update panel.
Step 1.
Create a Class file name named as WebMsgBox.cs

Step 2.
Copy the follwoing code in that cs file

using System;
using Microsoft.VisualBasic;
using System.Text;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;



namespace TestWebMsgApp
{
public class WebMsgBox
{
protected static Hashtable handlerPages = new Hashtable();
private WebMsgBox()
{
}

public static void Show(string Message)
{
if (!(handlerPages.Contains(HttpContext.Current.Handler)))
{
Page currentPage = (Page)HttpContext.Current.Handler;
if (!((currentPage == null)))
{
Queue messageQueue = new Queue();
messageQueue.Enqueue(Message);
handlerPages.Add(HttpContext.Current.Handler, messageQueue);
currentPage.Unload += new EventHandler(CurrentPageUnload);
}
}
else
{
Queue queue = ((Queue)(handlerPages[HttpContext.Current.Handler]));
queue.Enqueue(Message);
}
}

private static void CurrentPageUnload(object sender, EventArgs e)
{
Queue queue = ((Queue)(handlerPages[HttpContext.Current.Handler]));
if (queue != null)
{
StringBuilder builder = new StringBuilder();
int iMsgCount = queue.Count;
builder.Append("<script language='javascript'>");
string sMsg;
while ((iMsgCount > 0))
{
iMsgCount = iMsgCount - 1;
sMsg = System.Convert.ToString(queue.Dequeue());
sMsg = sMsg.Replace("\"", "'");
builder.Append("alert( \"" + sMsg + "\" );");
}
builder.Append("</script>");
handlerPages.Remove(HttpContext.Current.Handler);
HttpContext.Current.Response.Write(builder.ToString());
}
}
static public void DisplayAJAXMessage(Control page, string msg)
{

string myScript = String.Format("alert('"+ msg +"');",msg);
//string myScript = String.Format("alert('"{0}"');",msg);


ScriptManager.RegisterStartupScript(page, page.GetType(),
"MyScript", myScript, true);
}


}

}

Step 3.
Now call the method show from the CS file of your webpage

TestWebMsgApp.WebMsgBox.Show("Hello");

Now you can see the server side message box in the web page when ajax is using