I am trying to build a Web Application using Visual Studio 2005 and C# 2005. I need to accept a date in a particular textbox. I tried to use AJAX Calendar Extender for the purpose. I have added AJAX Script Manager and CalendarExtender controls to the webpage and set the TargetControlId of CalendarExtender to the proper textbox id. But when I display the webpage (using Debug -> Start Without Debugging) and click inside the textbox nothing happens. I even tried to add an image control to the form and set the PopupButtonId of the CalendarExtender to the image, but even then I am unable to display the calendar control. What am I doing wrong??

I had only dropped the required controls on the webform and all the code was auto generated. The generated code was as follows:

```
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" Namespace="System.Web.UI" TagPrefix="asp" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
     <form id="form1" runat="server">
     <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
     <cc1:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="TextBox1"></cc1:CalendarExtender>
     <asp:ScriptManager id="ScriptManager1" runat="server"></asp:ScriptManager>
     </form>
</body>
</html>

```