Loading ScriptManager only once either from Master page or Content page

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 HoverMenuExtender 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.

All the other content pages which has ScriptManager throws the error Only one instance of a ScriptManager can be added to t开发者_JS百科he page. I don't want to work on most of the content pages again to remove ScriptManager.

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.

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Take a look at ScriptManagerProxy. This is what I think you need.