title: Loading ScriptManager only once either from Master page or Content page
body: <p>I have an web application of 200 web pages and all has a single master page. Most of the content pages use AJAX controls so most of content pages has its own ScriptManager. Now I have a requirement to add a link with <strong>HoverMenuExtender</strong> control and for that I need to put ScriptManager in the Master page, but it is working only in the content pages where there is not ScriptManager. </p>
  
  <p>All the other content pages which has ScriptManager throws the error <code>Only one instance of a ScriptManager can be added to the page</code>. I don't want to work on most of the content pages again to remove ScriptManager. </p>
  
  <p>Is there any easy way to do this something like coding in Master page which decides if there is already ScriptManager already, then don't load it. </p>