if (document.images) {

    img1on = new Image();
    img1on.src = "images/nav/home_over.gif";
    img2on = new Image();
    img2on.src = "images/nav/services_over.gif";
    img3on = new Image();
    img3on.src = "images/nav/news_over.gif";
    img4on = new Image();
    img4on.src = "images/nav/wip_over.gif";
    img5on = new Image();
    img5on.src = "images/nav/projects_over.gif";
    img6on = new Image();
    img6on.src = "images/nav/contact_over.gif";


    img1off = new Image();
    img1off.src = "images/nav/home_off.gif";
    img2off = new Image();
    img2off.src = "images/nav/services_off.gif";
    img3off = new Image();
    img3off.src = "images/nav/news_off.gif";
    img4off = new Image();
    img4off.src = "images/nav/wip_off.gif";
    img5off = new Image();
    img5off.src = "images/nav/projects_off.gif";
    img6off = new Image();
    img6off.src = "images/nav/contact_off.gif";

}

function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}

function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}