function SetPosition() {
    var TopLayerWidth = $('.TopLayer').outerWidth();
    var TopLayerHeight = $('.TopLayer').outerHeight();
    $('.TopLayer_bg').css({ "opacity": 0.6 });

    var width = $(window).width();
    var height = $(window).height();
    var left = (width - TopLayerWidth) / 2;
    var top = (height - TopLayerHeight) / 2;
    left = left > 0 ? left : 0;
    top = top > 0 ? top : 0;
    $('.TopLayer').css({ top: top, left: left });
}

function ShowTopLayer() {

    if ($(".TopLayer").length && $(".TopLayer_bg").length) {
        SetPosition();
        $('.TopLayer_bg, .TopLayer').show();

        $(window).bind('scroll resize load', function () {
            SetPosition();
        });
    }
}

function HideTopLayer() {
    if ($(".TopLayer").length && $(".TopLayer_bg").length) {
        $('.TopLayer_bg, .TopLayer').hide();
    }
}