<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
header('Expires: Sat, 03 Aug 2013 00:00:00 GMT');
header('Last-Modified: ' . gmdate( 'D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', false);
header('Pragma: no-cache');