function newImage(arg) {
    if (document.images) {
        rslt = new Image();
        rslt.src = arg;
        return rslt;
    }
}

function changeImages() {
    if (document.images && (preloadFlag == true)) {
        for (var i = 0; i < changeImages.arguments.length; i += 2) {
            document[changeImages.arguments[i]].src = changeImages.arguments[i + 1];
        }
    }
}

var preloadFlag = false;
function preloadImages() {
    if (document.images) {
        nav02 = newImage("images/nav/nav02_over.gif");
        nav03 = newImage("images/nav/nav03_over.gif");
        nav04 = newImage("images/nav/nav04_over.gif");
        nav05 = newImage("images/nav/nav05_over.gif");
        nav06 = newImage("images/nav/nav06_over.gif");
        nav07 = newImage("images/nav/nav07_over.gif");
        nav08 = newImage("images/nav/nav08_over.gif");
        nav09 = newImage("images/nav/nav09_over.gif");
        prd01 = newImage("images/prd/prd01_over.png");
        prd02 = newImage("images/prd/prd02_over.png");
        prd03 = newImage("images/prd/prd03_over.png");
        prd04 = newImage("images/prd/prd04_over.png");
        preloadFlag = true;
    }
}