function fdn_pop(url,ref_id)
{
    if ((/filedownloader/i.test(navigator.userAgent.toLowerCase())) || ((/fdnet/i.test(navigator.userAgent.toLowerCase()))))
    {
        if (url != '')
        {
            document.location.href = 'fdn://filedownloader.net/?'+url;
            alert('Links passed to the Filedownloader Program!');
        }
        else
        {
            alert('There are no supported links on this page!');
        }
    }
    else
    {
        if (confirm("Your system does not have Filedownloader installed to use this button.\n\r\n\r"+
                    "Do you want to visit official Filedownloader`s site to download latest version?"))
        {
            document.location.href = 'http://filedownloader.net/'+(ref_id ? ref_id+'/' : '');
        }
    }
}