PHP字符过滤方法

function str_filter_replace($str){ ???if (empty($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("<SCRIPT>", "", $str); ???$str = str_replace("</SCRIPT>", "", $str); ???$str = str_replace("<script>", "", $str); ???$str = str_replace("</script>", "", $str); ???$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("<br />",chr(13),$str); ???$str=str_replace("‘‘","‘",$str); ???$str=str_replace("css","‘",$str); ???$str=str_replace("CSS","‘",$str); ???return $str;}