if (document.images) {            // Active Images
            img1on = new Image();
            img1on.src = "images/menu_home_on.gif";
            img1off = new Image();
            img1off.src = "images/menu_home.gif";
            img2on = new Image();
            img2on.src = "images/menu_play_on.gif";
            img2off = new Image();
            img2off.src = "images/menu_play.gif";
            img3on = new Image();
            img3on.src = "images/menu_helpful_on.gif";
            img3off = new Image();
            img3off.src = "images/menu_helpful.gif";
            img4on = new Image();
            img4on.src = "images/menu_benefits_on.gif";
            img4off = new Image();
            img4off.src = "images/menu_benefits.gif";
            img5on = new Image();
            img5on.src = "images/menu_signs_on.gif";
            img5off = new Image();
            img5off.src = "images/menu_signs.gif";
            img6on = new Image();
            img6on.src = "images/menu_process_on.gif";
            img6off = new Image();
            img6off.src = "images/menu_process.gif";
            img7on = new Image();
            img7on.src = "images/menu_who_on.gif";
            img7off = new Image();
            img7off.src = "images/menu_who.gif";
            img8on = new Image();
            img8on.src = "images/menu_therapist_on.gif";
            img8off = new Image();
            img8off.src = "images/menu_therapist.gif";
            img9on = new Image();
            img9on.src = "images/menu_biography_on.gif";
            img9off = new Image();
            img9off.src = "images/menu_biography.gif";
            img10on = new Image();
            img10on.src = "images/menu_testimonials_on.gif";
            img10off = new Image();
            img10off.src = "images/menu_testimonials.gif";
            img11on = new Image();
            img11on.src = "images/menu_additional_on.gif";
            img11off = new Image();
            img11off.src = "images/menu_additional.gif";
            img12on = new Image();
            img12on.src = "images/menu_contact_on.gif";
            img12off = new Image();
            img12off.src = "images/menu_contact.gif";
            img13on = new Image();
            img13on.src = "images/menu_links_on.gif";
            img13off = new Image();
            img13off.src = "images/menu_links.gif";
            img14on = new Image();
            img14on.src = "images/menu_what_on.gif";
            img14off = new Image();
            img14off.src = "images/menu_what.gif";
            img15on = new Image();
            img15on.src = "images/menu_news_on.gif";
            img15off = new Image();
            img15off.src = "images/menu_news.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");
        }
}