过滤多余回车

$str=preg_replace("/\s+/", " ", $str);

注释

$str=preg_replace("/<\!--.*?-->/si","",$str);

过滤DOCTYPE

$str=preg_replace("/<(\!.*?)>/si","",$str);

过滤html标签

$str=preg_replace("/<(\/?html.*?)>/si","",$str);

过滤head标签

$str=preg_replace("/<(\/?head.*?)>/si","",$str);

过滤meta标签

$str=preg_replace("/<(\/?meta.*?)>/si","",$str);

过滤body标签

$str=preg_replace("/<(\/?body.*?)>/si","",$str);

过滤link标签

$str=preg_replace("/<(\/?link.*?)>/si","",$str);

过滤form标签

$str=preg_replace("/<(\/?form.*?)>/si","",$str);

过滤COOKIE标签

$str=preg_replace("/cookie/si","COOKIE",$str);

过滤applet标签

$str=preg_replace("/<(applet.*?)>(.*?)<(\/applet.*?)>/si","",$str);

过滤applet标签

$str=preg_replace("/<(\/?applet.*?)>/si","",$str);

过滤style标签

$str=preg_replace("/<(style.*?)>(.*?)<(\/style.*?)>/si","",$str);

过滤style标签

$str=preg_replace("/<(\/?style.*?)>/si","",$str);

过滤title标签

$str=preg_replace("/<(title.*?)>(.*?)<(\/title.*?)>/si","",$str);

过滤title标签

$str=preg_replace("/<(\/?title.*?)>/si","",$str);

过滤object标签

$str=preg_replace("/<(object.*?)>(.*?)<(\/object.*?)>/si","",$str);

过滤object标签

$str=preg_replace("/<(\/?objec.*?)>/si","",$str);

过滤noframes标签

$str=preg_replace("/<(noframes.*?)>(.*?)<(\/noframes.*?)>/si","",$str);

过滤noframes标签

$str=preg_replace("/<(\/?noframes.*?)>/si","",$str);

过滤frame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script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);

来源：守望的麦子