header('Expires: 0');
header('Last-Modified: '. gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-store, no-cahe, must-revalidate');
//ie专用
header('Cache-Control: post-chedk=0, pre-check=0', false);
//for HTTP/1.0
header('Pragma: no-cache');