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("", "", $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;}