判断操作系统位数

function getDomain($protocol = true){
    $domain = '';
    if ($protocol){
        $domain .= ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') || (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')) ? 'https://' : 'http://';
    }

        if($_SERVER['HTTP_HOST']){
            $domain .= $_SERVER['HTTP_HOST'];
        }else{
            $domain .= $_SERVER['SERVER_NAME'];
            if ($_SERVER['SERVER_PORT'] != 80){
                $domain .= ':'.$_SERVER['SERVER_PORT'];
            }
        }

        return $domain;
}