function preloader() {
	if (document.images) {
		a01a = new Image(71,36);
		a01a.src = '/.images/layout/submenu/ba-impress.jpg';
		a01b = new Image(71,36);
		a01b.src = '/.images/layout/submenu/bb-impress.jpg';
	}
}

function on(imgName) {
	if (document.images) {
		document [imgName].src = eval(imgName + "b.src");
	}
}

function off(imgName) {
	if (document.images) {
		document [imgName].src = eval(imgName + "a.src");
	}
}