if (document.images) {
    homebuttonup = new Image();
    homebuttonup.src = "/assets/home_button.jpg";
    homebuttondown = new Image();
    homebuttondown.src = "/assets/home_rollover.jpg";

    upcomingbuttonup = new Image();
    upcomingbuttonup.src = "/assets/upcoming_button.gif";
    upcomingbuttondown = new Image();
    upcomingbuttondown.src = "/assets/upcoming_rollover.gif";

    hostbuttonup = new Image();
    hostbuttonup.src = "/assets/host_button.gif";
    hostbuttondown = new Image();
    hostbuttondown.src = "/assets/host_rollover.gif";

    volunteerbuttonup = new Image();
    volunteerbuttonup.src = "/assets/volunteer_button.jpg";
    volunteerbuttondown = new Image();
    volunteerbuttondown.src = "/assets/volunteer_rollover.jpg";

    sponsorbuttonup = new Image();
    sponsorbuttonup.src = "/assets/sponsor_button.jpg";
    sponsorbuttondown = new Image();
    sponsorbuttondown.src = "/assets/sponsor_rollover.jpg";

    contactbuttonup = new Image();
    contactbuttonup.src = "/assets/contact_button.jpg";
    contactbuttondown = new Image();
    contactbuttondown.src = "/assets/contact_rollover.jpg";
}

function buttondown(buttonname) {
    if (document.images) {
        document[buttonname].src = eval(buttonname + "down.src");
    }
}

function buttonup(buttonname) {
    if (document.images) {
        document[buttonname].src = eval(buttonname + "up.src");
    }
}