public function browserVersion()
    {
        $UserAgent = self::agent();
        $B_Agent = self::Browser()['agent'];
        if ($B_Agent !== null) {
            $known = ['Version', $B_Agent, 'other'];
            $pattern = '#(?<browser>'.implode('|', $known).
            ')[/ ]+(?<version>[0-9.|a-zA-Z.]*)#';
            if (!preg_match_all($pattern, $UserAgent, $matches)) {
            }
            $i = count($matches['browser']);
            if ($i != 1) {
                if (strripos($UserAgent, 'Version') < strripos($UserAgent, $B_Agent)) {
                    $Version = $matches['version'][0];
                } else {
                    $Version = $matches['version'][0];
                }
            } else {
                $Version = $matches['version'][0];
            }
        }

        return $Version;
    }