static public function uuid($separator=true)
    {
        if (function_exists('com_create_guid')){
            return com_create_guid();
        }else{
            mt_srand((double)microtime()*10000);    //optional for php 4.2.0 and up.
            $charid = strtoupper(md5(uniqid(mt_rand(), true)));
            $hyphen = $separator ? chr(45) : '';  // "-"
            $uuid = substr($charid, 0, 8).$hyphen
            .substr($charid, 8, 4).$hyphen
            .substr($charid,12, 4).$hyphen
            .substr($charid,16, 4).$hyphen
            .substr($charid,20,12);
            //$uuid = chr(123) . $uuid .chr(125);  // "{" "}"
            return $uuid;
        }
    }