// Displays Offer Pop-up.
function displayOffer(popup_url, redirect_url) {
    location.href = redirect_url;
    offerwin = window.open(popup_url, 'vgdp_offer', 'location=no,status=no,scrollbars=no,resizable=no,toolbar=no,width=385,height=444');
    offerwin.focus();
}