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) {
                mop_b = newImage("../images/buttons/mop_on.gif");
                revitalize_b = newImage("../images/buttons/revitalize_on.gif");
                df_b = newImage("../images/buttons/dfi_on.gif");
			
                preloadFlag = true;
        }
}