What is the use of ScriptmanagerProxy class in AJAX?

Answer:

As we know that,we can have only one ScriptManager control on to a Page.But if we have a scenario,that we have to register any script or use any web service in a particular page(content page) and ScriptManager is already there in a master page,then we can use the ScriptManagerProxy control to add scripts or give reference of web service to any content pages.Because if we give reference or add script in a master page,then every-time it will be referencing or adding from any page which is inheriting master page.