if (document.images) {
    preload_image_object = new Image();
    // set image url
    image_url = new Array();
    image_url[0] = "/Images/NavigationAboutUs.png";
    image_url[1] = "/Images/NavigationProducts.png";
    image_url[2] = "/Images/NavigationWhereToFindUs.png";
    image_url[3] = "/Images/NavigationInTheNews.png";
    
    var i = 0;
    for (i = 0; i <= image_url.length; i++) {
        preload_image_object.src = image_url[i];
    }
}
function MenuOver(element, file) {
    element.src = file;
}
function MenuOutId(ele, file) {
    document.getElementById(ele).src = file;
}
function MenuOut(element, file) {
    element.src = file;
}
function HideMenu(ele) {
    document.getElementById(ele).style.visibility = "hidden";
    if (document.getElementById('hideWhenShowMenu') != null)
        document.getElementById('hideWhenShowMenu').style.visibility = 'visible';
}
function ShowMenu(ele) {
    document.getElementById(ele).style.visibility = "visible";
    if (document.getElementById('hideWhenShowMenu') != null)
        document.getElementById('hideWhenShowMenu').style.visibility = 'hidden';
}

function SwapImage(obj, src) {
    obj.src = src;
    return true;
}