ASP.NET: Configure AjaxControlToolKit in web.config file

1. Install the Ajax Control Toolkit as described in: http://www.asp.net/ajaxlibrary/act.ashx
2. Modify the web.config by adding the entries below: (all are case sensitive)
• <add assembly="AjaxControlToolkit, Version=3.5.40412.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e"/>  Goes between <assemblies></assemblies> tag.
• <add tagPrefix="ajaxToolkit" namespace="AjaxControlToolkit" assembly="AjaxControlToolkit, Version=3.5.40412.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e"/> Goes between <controls></controls> tag.
3. If you’ve installed some other version of the tool kit then make sure to replace a value of the Version attribute of both entries above.
4. To get the version just right click on the AjaxControlToolkit.dll and get the value of Assembly Version.
5. Now on the .aspx page include the "Ajax Control" for example "Tab Container" as follow:
   <ajaxToolkit:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="1"      Width="316px"> </ajaxToolkit:TabContainer>