详细介绍PHP过滤常见html标签的正则表达式

htmlentities(string,quotestyle,character-set)

<br/>

strip_tags(string,"");

xxx

strip_tags(string,"
");

$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.*?)>(.*?)