It is quite common to use Response.Redirect from an event handler to redirect the user's browser to a different page. This scenario is supported from asynchronous postbacks too. In this case, the redirect will use client-side JavaScript to execute instead of the redirect headers that are used in the case of synchronous postbacks. Cookies that are set from the asynchronous postback will be effectively saved, which enables scenarios like using asynchronous postbacks for login pages.