关于点后退按钮显示"网页已经过期"请添加如下相应的代码：
HTM网页
<META HTTP-EQUIV="pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache, must-revalidate">
<META HTTP-EQUIV="expires" CONTENT="Wed, 26 Feb 1997 08:21:57 GMT">
或者<META HTTP-EQUIV="expires" CONTENT="0">
PHP网页
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Cache-Control: no-cache, must-revalidate");
header("Pragma: no-cache");
OR
header('Last-Modified: '.gmdate('D, d M Y H:i:s', TIME).' GMT');
// TIME = time();
header('Expires: '.gmdate('D, d M Y H:i:s', TIME+CACHE_PAGE_INDEX_TTL).' GMT');
header('Cache-Control: max-age='.CACHE_PAGE_INDEX_TTL.', must-revalidate');