function getRandomBackground()
    {
        var bgImages = new Array();
        bgImages[0] = "./pix/tailgate.jpg";
        bgImages[1] = "./pix/grotto_winter.jpg";
        bgImages[2] = "./pix/library_winter.jpg";
        bgImages[3] = "./pix/dome_winter.jpg";

        var preload = new Array();

        for(var i=0; i<bgImages.length; i++)
        {
            preload[i] = new Image();
            preload[i].src = bgImages[i].src;
        }

        var exd = new Date();
        var randid = exd.getTime() % bgImages.length;

        bkgrnd = document.getElementById("toplogo");
        bkgrnd.style.background = "url('"+bgImages[randid]+"') top left no-repeat";
    }