ASP.NET Ajax Controller

Java Script
(AjaxScript.js)

var xmlHttp;
var elementId;
var urlpage = "AjaxController.aspx";

function showContent(id, querystring)
{
elementId = id;
xmlHttp=GetXmlHttpObject();
if (xmlHttp==null)
{
alert ("Your browser does not support AJAX!");
return;
}
var url= urlpage;
url=url + querystring;
//url=url+"&sid="+Math.random();
xmlHttp.onreadystatechange=getContent;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}

function getContent()
{
if (xmlHttp.readyState==4)
{
document.getElementById(elementId).innerHTML=xmlHttp.responseText;
}
}

function GetXmlHttpObject()
{
var xmlHttp=null;
try
{
// Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}
catch (e)
{
// Internet Explorer
try
{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}

ASP.NET Page
(AjaxController.aspx)

Page

<%@ Page Language="vb" AutoEventWireup="false" Codebehind="AjaxController.aspx.vb" Inherits="AjaxExperiment.Content"%>

<% showOutput() %>

Note: Change the inheritance to your project name. "AjaxExperiment.content"

Code Behind

Public Function showOutput()
If Request.QueryString.Item("key") = 1 Then
Response.Write("Hello AJAX")

Else
Response.Write("Hello World")
End If
End Function