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：

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 $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