title: Intercept page exit event
body: <p>When editing a page within my system, a user might decide to navigate to another website and in doing so could lose all the edits they have not saved.</p>
  <p>I would like to intercept any attempt to go to another page and prompt the user to be sure they want this to happen since they could potentially lose their current work.</p>
  <p>Gmail does this in a very similar way.  For example, compose a new email, start typing into the message body and enter a new location in the address bar (say twitter.com or something).  It will prompt asking &quot;Are you sure?&quot;</p>
  <p>Ideas how to replicate this?  I'm targeting IE8, but would like to be compatible with Firefox and Chrome also.</p>