php中html字符串过滤函数详解

function StripHTML($string){
 $pattern=array ("']*?>.*?'si", "']*?>.*?'si",  "'<[/!]*?[^<>]*?>'si",  "'([rn])[s]+'",  "'&(quot|#34);'i",  "'&(amp|#38);'i",  "'&(lt|#60);'i",  "'&(gt|#62);'i",  "'&(nbsp|#160);'i",  "'&(iexcl|#161);'i",  "'&(cent|#162);'i",  "'&(pound|#163);'i",  "'&(copy|#169);'i",  "'&#(d+);'e");
 $replace=array ('', '', "1", '', "&", "<", ">", ' ', chr(161), chr(162), chr(163), chr(169), "chr(1)");
 return preg_replace ($pattern, $replace, $str);
}

strip_tags(string,"");

strip_tags(string,"

");

//php 批量过滤post,get敏感数据
if (get_magic_quotes_gpc()) {
$_GET = stripslashes_array($_GET);
$_POST = stripslashes_array($_POST);
}

function stripslashes_array(&$array) {
while(list($key,$var) = each($array)) {
if ($key != 'argc' && $key != 'argv' && (strtoupper($key) != $key || ''.intval($key) == "$key")) {
if (is_string($var)) {
$array[$key] = stripslashes($var);
}
if (is_array($var))  {
$array[$key] = stripslashes_array($var);
}
}
}
return $array;
}
         //--------------------------

// 替换HTML尾标签,为过滤服务 www.111com.net
//--------------------------
function lib_replace_end_tag($str)
{
if (empty($str)) return false;
$str = htmlspecialchars($str);
$str = str_replace( '/', "", $str);
$str = str_replace("", "", $str);
$str = str_replace(">", "", $str);
$str = str_replace("<", "", $str);
$str = str_replace("", "", $str);
$str = str_replace("", "", $str);
$str=str_replace("select","select",$str);
$str=str_replace("join","join",$str);
$str=str_replace("union","union",$str);
$str=str_replace("where","where",$str);
$str=str_replace("insert","insert",$str);
$str=str_replace("delete","delete",$str);
$str=str_replace("update","update",$str);
$str=str_replace("like","like",$str);
$str=str_replace("drop","drop",$str);
$str=str_replace("create","create",$str);
$str=str_replace("modify","modify",$str);
$str=str_replace("rename","rename",$str);
$str=str_replace("alter","alter",$str);
$str=str_replace("cas","cast",$str);
$str=str_replace("&","&",$str);
$str=str_replace(">",">",$str);
$str=str_replace("<","<",$str);
$str=str_replace(" ",chr(32),$str);
$str=str_replace(" ",chr(9),$str);
$str=str_replace("    ",chr(9),$str);
$str=str_replace("&",chr(34),$str);
$str=str_replace("'",chr(39),$str);
$str=str_replace("
",chr(13),$str);
$str=str_replace("''","'",$str);
$str=str_replace("css","'",$str);
$str=str_replace("CSS","'",$str);

return $str;

}

引用是直接这样：
$xxx = htmlspecialchars($_POST['xxx']);
或者
$xxx = htmlspecialchars($_GET['xxx']);