PHP clears html formatted code

$descclear = str_replace("\r","",$descclear);//过滤换行
$descclear = str_replace("\n","",$descclear);//过滤换行
$descclear = str_replace("\t","",$descclear);//过滤换行
$descclear = str_replace("\r\n","",$descclear);//过滤换行
$descclear = preg_replace("/\s+/", " ", $descclear);//过滤多余回车
$descclear = preg_replace("/<[ ]+/si","<",$descclear); //过滤<__("<"号后面带空格)
$descclear = preg_replace("/<\!--.*?-->/si","",$descclear); //过滤html注释
$descclear = preg_replace("/<(\!.*?)>/si","",$descclear); //过滤DOCTYPE
$descclear = preg_replace("/<(\/?html.*?)>/si","",$descclear); //过滤html标签
$descclear = preg_replace("/<(\/?head.*?)>/si","",$descclear); //过滤head标签
$descclear = preg_replace("/<(\/?meta.*?)>/si","",$descclear); //过滤meta标签
$descclear = preg_replace("/<(\/?body.*?)>/si","",$descclear); //过滤body标签
$descclear = preg_replace("/<(\/?link.*?)>/si","",$descclear); //过滤link标签
$descclear = preg_replace("/<(\/?form.*?)>/si","",$descclear); //过滤form标签
$descclear = preg_replace("/cookie/si","COOKIE",$descclear); //过滤COOKIE标签
$descclear = preg_replace("/<(applet.*?)>(.*?)<(\/applet.*?)>/si","",$descclear); //过滤applet标签
$descclear = preg_replace("/<(\/?applet.*?)>/si","",$descclear); //过滤applet标签
$descclear = preg_replace("/<(style.*?)>(.*?)<(\/style.*?)>/si","",$descclear); //过滤style标签
$descclear = preg_replace("/<(\/?style.*?)>/si","",$descclear); //过滤style标签
$descclear = preg_replace("/<(title.*?)>(.*?)<(\/title.*?)>/si","",$descclear); //过滤title标签
$descclear = preg_replace("/<(\/?title.*?)>/si","",$descclear); //过滤title标签
$descclear = preg_replace("/<(object.*?)>(.*?)<(\/object.*?)>/si","",$descclear); //过滤object标签
$descclear = preg_replace("/<(\/?objec.*?)>/si","",$descclear); //过滤object标签
$descclear = preg_replace("/<(noframes.*?)>(.*?)<(\/noframes.*?)>/si","",$descclear); //过滤noframes标签
$descclear = preg_replace("/<(\/?noframes.*?)>/si","",$descclear); //过滤noframes标签
$descclear = preg_replace("/<(i?frame.*?)>(.*?)<(\/i?frame.*?)>/si","",$descclear); //过滤frame标签
$descclear = preg_replace("/<(\/?i?frame.*?)>/si","",$descclear); //过滤frame标签
$descclear = preg_replace("/<(script.*?)>(.*?)<(\/script.*?)>/si","",$descclear); //过滤script标签
$descclear = preg_replace("/<(\/?script.*?)>/si","",$descclear); //过滤script标签
$descclear = preg_replace("/javascript/si","Javascript",$descclear); //过滤script标签
$descclear = preg_replace("/vbscript/si","Vbscript",$descclear); //过滤script标签
$descclear = preg_replace("/on([a-z]+)\s*=/si","On\\1=",$descclear); //过滤script标签
$descclear = preg_replace("/&#/si","&＃",$descclear); //过滤script标签，如javAsCript:alert();
//使用正则替换
$pat = "/<(\/?)(script|i?frame|style|html|body|li|i|map|title|img|link|span|u|font|table|tr|b|marquee|td|strong|div|a|meta|\?|\%)([^>]*?)>/isU";
$descclear = preg_replace($pat,"",$descclear);