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) {
                nav_listings_over = newImage("images/nav_listings_over.gif");
                nav_open_nav_listings_over = newImage("images/nav_open_over.gif");
                nav_listwith_nav_listings_over = newImage("images/nav_listwith_over.gif");
                nav_contact_nav_listings_over = newImage("images/nav_contact_over.gif");
                nav_home_nav_listings_over = newImage("images/nav_home_over.gif");
                preloadFlag = true;
        }
}