title: ASP.Net Ajax Collapsible Extender ViewState Issue
body: <p>I am currently working on an advanced web application that contains a number of Dynamically Rendered pages.  The pages are standard pages which contain a place holder into which the main content is rendered from a combination of Xml and Xslt.</p>
  
  <p>I have recently been attempting to add a ASP.Net Ajax Toolkit collapsible entender to allow the collapsing and extending of the panels which are dynamically rendered.  I have added the extender markup to our main xslt template and all is fine.  Well all is fine until a post back takes place and the panels return to their intial state.  So, for example, if I load the page with the panels collapsed then after postback the page fails to reset any open panels,  The problem is caused by the fact that I store the dynamic content in the viewstate itself and once the page is loaded just retrieve it from the viewstate rather than re-render the Xml.</p>
  
  <p>Phew.... there is the background to the problem.</p>
  
  <p>Now the main question.  How on earth can you interact with the extender in Javascript.  I have spent days convinced that I could cache the state in a page variable client side and then reapply the state post postback.  However, there appears to be no documentation or knowledge of how to accomplish this.  The best I have found is some very simple javascript which will allow you to register a couple of events to catch when the panel is extended or collapsed.</p>
  
  <p>All I want to do is interact and cache each panels state.  Can anyone suggest anything?</p>