php禁止頁面快取輸出的程式碼

<?php
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . 'GMT');
header('Cache-Control: no-cache, must-revalidate');
header('Pragma: no-cache');
?>