if (document.images) {            // Active Images
            img1on = new Image();
            img1on.src = "images/head1a.gif";
            img2on = new Image();
            img2on.src = "images/head2a.gif";
            img3on = new Image();
            img3on.src = "images/head3a.gif";
            img4on = new Image();
            img4on.src = "images/head4a.gif";
            img5on = new Image();
            img5on.src = "images/head5a.gif";
            img7on = new Image();
            img7on.src = "images/head7a.gif";
            img8on = new Image();
            img8on.src = "images/head8a.gif";
            img9on = new Image();
            img9on.src = "images/head9a.gif";
            img12on = new Image();
            img12on.src = "images/head10a.gif";
            img10on = new Image();
            img10on.src = "images/home1a.gif";
            img11on = new Image();
            img11on.src = "images/contact1a.gif";
            img13on = new Image();
            img13on.src = "images/head11a.gif";

            img1off = new Image();
            img1off.src = "images/head1.gif";
            img2off = new Image();
            img2off.src = "images/head2.gif";
            img3off = new Image();
            img3off.src = "images/head3.gif";
            img4off = new Image();
            img4off.src = "images/head4.gif";
            img5off = new Image();
            img5off.src = "images/head5.gif";
            img7off = new Image();
            img7off.src = "images/head7.gif";
            img8off = new Image();
            img8off.src = "images/head8.gif";
            img9off = new Image();
            img9off.src = "images/head9.gif";
            img11off = new Image();
            img11off.src = "images/contact1.gif";
            img10off = new Image();
            img10off.src = "images/home1.gif";
            img12off = new Image();
            img12off.src = "images/head10.gif";
            img13off = new Image();
            img13off.src = "images/head11.gif";

        }

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

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