function PreLoadImages() {
    about_on = new Image(); about_on.src = "images/about_nav.gif";
    about_off = new Image(); about_off.src = "images/about_nav.jpg";
    service_on = new Image(); service_on.src = "images/services_nav.gif";
    service_off = new Image(); service_off.src = "images/services_nav.jpg";
    tech_on = new Image(); tech_on.src = "images/tech_nav.gif";
    tech_off = new Image(); tech_off.src = "images/tech_nav.jpg";
    clients_on = new Image(); clients_on.src = "images/clients_nav.gif";
    clients_off = new Image(); clients_off.src = "images/clients_nav.jpg";
}
function movr(k) {
    eval('document.images.' + k + '.src=' + k + '_on.src');
}

function mout(k) {
    eval('document.images.' + k + '.src=' + k + '_off.src');
}