title: How long do PHP static variables persist?
body: <p>How long do PHP static variables persist, i.e. how long does a "PHP run" persist?  With say a command line program there is a defined start and end, but in web w/ AJAX I don't know how to define this.</p>
  
  <p>Here are 3 ways I've seen a PHP script started.</p>
  
  <ol>
  <li>User (Requesing a PHP page)</li>
  <li>Javacript calling PHP (AJAX)</li>
  <li>PHP calling more PHP via a header()</li>
  </ol>
  
  <p>In my actual application I have javascript call a php script via AJAX that script uses the header() to reload the site.  This would be consideredt two different runs.  Each has their own static variables that do not relate.</p>