private function emailGetMetaInfo()
    {
        $cfg = $this->from->cfg;
        $meta = array(
            'Submitted on '.\date('F j, Y, g:ia'),  // March 10, 2001, 5:16pm
            'URL' => Html::getSelfUrl(array(), array('fullUrl'=>true,'chars'=>false)),
            !empty($_COOKIE['referer'])
                ? 'Came to '.$_SERVER['HTTP_HOST'].' via: '.$_COOKIE['referer']
                : null,
            'Form processor ver' => $cfg['version'],
            'User Agent' => !empty($_SERVER['HTTP_USER_AGENT'])
                ? $_SERVER['HTTP_USER_AGENT']
                : 'unknown',
            'User\'s IP address' => $_SERVER['REMOTE_ADDR'],
            'Session ID' => \session_id(),
        );
        $metaCollect = $this->collected;    // 'screen_width','screen_height','screen_colorDepth'
        unset($metaCollect['name']);
        unset($metaCollect['email']);
        $meta = \array_merge($meta, $metaCollect, $cfg['email']['addMetaInfo']);
        $str = '';
        foreach ($meta as $k => $v) {
            if (\is_int($k) && empty($v)) {
                continue;
            }
            $str = $k.': '.$v."\n";
        }
        return $str;
    }