我们常常会用到PHP过滤一些标签的功能，比如过滤链接标签、过滤script标签等等，下面就介绍一下PHP过滤常用标签的正则表达式代码：
复制代码代码如下:
$str=preg_replace("//s+/", " ", $str); //过滤多余回车
$str=preg_replace("/<[ ]+/si","<",$str); //过滤<__("<"号后面带空格)
$str=preg_replace("/</!–.*?–>/si","",$str); //注释
$str=preg_replace("/<(/!.*?)>/si","",$str); //过滤DOCTYPE
$str=preg_replace("/<(//?html.*?)>/si","",$str); //过滤html标签
$str=preg_replace("/<(//?head.*?)>/si","",$str); //过滤head标签
$str=preg_replace("/<(//?meta.*?)>/si","",$str); //过滤meta标签
$str=preg_replace("/<(//?body.*?)>/si","",$str); //过滤body标签
$str=preg_replace("/<(//?link.*?)>/si","",$str); //过滤link标签
$str=preg_replace("/<(//?form.*?)>/si","",$str); //过滤form标签
$str=preg_replace("/cookie/si","COOKIE",$str); //过滤COOKIE标签
$str=preg_replace("/<(applet.*?)>(.*?)<(//applet.*?)>/si","",$str); //过滤applet标签
$str=preg_replace("/<(//?applet.*?)>/si","",$str); //过滤applet标签
$str=preg_replace("/<(style.*?)>(.*?)<(//style.*?)>/si","",$str); //过滤style标签
$str=preg_replace("/<(//?style.*?)>/si","",$str); //过滤style标签
$str=preg_replace("/<(title.*?)>(.*?)<(//title.*?)>/si","",$str); //过滤title标签
$str=preg_replace("/<(//?title.*?)>/si","",$str); //过滤title标签
$str=preg_replace("/<(object.*?)>(.*?)<(//object.*?)>/si","",$str); //过滤object标签
$str=preg_replace("/<(//?objec.*?)>/si","",$str); //过滤object标签
$str=preg_replace("/<(noframes.*?)>(.*?)<(//noframes.*?)>/si","",$str); //过滤noframes标签
$str=preg_replace("/<(//?noframes.*?)>/si","",$str); //过滤noframes标签
$str=preg_replace("/<(i?frame.*?)>(.*?)<(//i?frame.*?)>/si","",$str); //过滤frame标签
$str=preg_replace("/<(//?i?frame.*?)>/si","",$str); //过滤frame标签
$str=preg_replace("/<(script.*?)>(.*?)<(//script.*?)>/si","",$str); //过滤script标签
$str=preg_replace("/<(//?script.*?)>/si","",$str); //过滤script标签
$str=preg_replace("/javascript/si","Javascript",$str); //过滤script标签
$str=preg_replace("/vbscript/si","Vbscript",$str); //过滤script标签
$str=preg_replace("/on([a-z]+)/s*=/si","On//1=",$str); //过滤script标签
$str=preg_replace("/&#/si","&＃",$str); //过滤script标签
