<?php setcookie("Purpose", $_SERVER["HTTP_PURPOSE"]); if (isset($_COOKIE['Purpose'])) { setcookie("Purpose", "", time() - 3600); echo "<h1>The cookie was set!</h1>"; echo "<p>Purpose: "; echo $_COOKIE['Purpose']; } else { echo "<h1>BAD BROWSER NO COOKIE</h1>"; } ?> <script> testRunner.notifyDone(); </script> <p>This test verifies that prefetches are sent with the HTTP request header <b>Purpose: prefetch</b>. To do this, the root page has a prefetch link targetting this subresource which contains a PHP script (resources/prefetch-purpose.php). That initial prefetch of this resource sets a cookie. Later, the root page sets window.location to target this script, which verifies the presence of the cookie, and generates the happy test output that you hopefully see right now.