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) {
        header_navigation_01_over = newImage("/images/header-navigation_01-over.gif");
        header_navigation_02_over = newImage("/images/header-navigation_02-over.gif");
        header_navigation_03_over = newImage("/images/header-navigation_03-over.gif");
        header_navigation_04_over = newImage("/images/header-navigation_04-over.gif");
        header_navigation_05_over = newImage("/images/header-navigation_05-over.gif");
        header_navigation_06_over = newImage("/images/header-navigation_06-over.gif");
        header_navigation_07_over = newImage("/images/header-navigation_07-over.gif");
        header_navigation_08_over = newImage("/images/header-navigation_08-over.gif");
        preloadFlag = true;
    }
}