# 讓它在過去就“失效”
header(”Expires: Mon, 26 Jul 1997 05:00:00 GMT”);
# 永遠是改動過的
header(”Last-Modified: “.gmdate(”D, d M Y H:i:s”).” GMT”);
# HTTP/1.1
header(”Cache -Control: no-store, no-cache , must-revalidate”);
header(”Cache -Control: post-check=0, pre-check=0″, false);
# HTTP/1.0
header(”Pragma: no-cache ”);
header("pragma:no-cache");
header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");