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) {
		button_background_over = newImage("/images/button-background-over.gif");
		nav_sub_over = newImage("/images/nav_sub_over.gif");
		//btn_home_over = newImage("/images/btn-home-over.gif");
		//btn_company_over = newImage("/images/btn-company-over.gif");
		//btn_investors_over = newImage("/images/btn-investors-over.gif");
		//btn_contactus_over = newImage("/images/btn-contactus-over.gif");
		preloadFlag = true;
	}
}