title: Automatically re-direct a user when session Times out or goes idle
body: <p>I want to have a timer going to run every 3 minutes on the page (javascript), to detect if a php session ($_SESSION) has timed out... and if so, redirect them automatically.</p>
  <p>A good example would be, a user logs in and runs up stairs, and never comes back down... I want the javascript to log them out with a simple redirect...</p>
  <p>Is this possible?  and how would I do such a thing?  I am using PHP and JavaScript.</p>
  <p>What <a href="https://stackoverflow.com/users/33732/rob-kennedy">Rob Kennedy</a> said below is exactly what I am looking for:</p>
  <blockquote>
  <p>...when the session times out,
  the browser should be told to navigate away from the current page.
  Some banks do this after a period of inactivity, for example.</p>
  </blockquote>