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_Layer_3_over = newImage("images/nav_Layer-3-over.jpg");
		nav_Layer_4_over = newImage("images/nav_Layer-4-over.jpg");
		nav_Layer_5_over = newImage("images/nav_Layer-5-over.jpg");
		nav_Layer_6_over = newImage("images/nav_Layer-6-over.jpg");
		nav_Layer_7_over = newImage("images/nav_Layer-7-over.jpg");
		nav_Layer_8_over = newImage("images/nav_Layer-8-over.jpg");
		nav_Layer_9_over = newImage("images/nav_Layer-9-over.jpg");
		preloadFlag = true;
	}
}