http://blogs.msdn.com/phaniraj/archive/2008/09/12/ajax-preview-2-declarative-instantiation-of-ajaxcontroltoolkit-controls.aspxToday ,we will talk about using the Declarative Syntax to instantiate certain AjaxControlToolkit Behaviors . Step 0: Figure out which are the script files needed for the Behavior to work and include the appropriate Script      en-USCommunityServer 2.1 SP1 (Build: 61025.2)