var preloadedImages = new Array();

function preloadImages(locationFolder) {
    if(document.images) {
            var i, args = preloadImages.arguments; 
            for(i=1; i<args.length; i++) {
                preloadedImages[args[i]]   = new Image(); 
                preloadedImages[args[i]].src   = locationFolder + args[i] + ".gif";
            }
    }
}

function rollOn(imageName) {
    if(document.images)
     document.images[imageName].src = preloadedImages[imageName + "_over"].src;
}

function rollOff(imageName) {
    if(document.images)
     document.images[imageName].src = preloadedImages[imageName + "_normal"].src;
}

function rollOnArrow(imageName, arrowType) {
    if(document.images)
     document.images[imageName].src = preloadedImages[arrowType].src;
}

function rollOffArrow(imageName) {
    if(document.images)
     document.images[imageName].src = preloadedImages["empty_13x13"].src;
}

function setRollOverMenuImage(imageName) {
    if(document.images)
     document.images["rollOverMenuImage"].src = preloadedImages[imageName].src;
}

preloadImages('../images/', 'home_normal', 'home_over', 'products_normal', 'products_over', 'support_normal', 'support_over', 'purchase_normal', 'purchase_over', 'downloads_normal', 'downloads_over', 'company_normal', 'company_over', 'library_normal', 'library_over');