gistfile1.aw

<!-- Server side code here -->
<?php
  if ($_POST['action'] === 'logout') {
    logout();
  }
?>

<!-- Client side code here -->
<form action="" method="post">
  <input type="hidden" name="action" value="logout" />
  <p><input type="submit" /></p>
</form>

<!-- This client-side code (html) is only sent from the server to the client if the logout button was pressed -->
<?php if ($_POST['action'] === 'logout'): ?>
  <p><b>You were logged out!</b></p>
<?php endif; ?>