var menuBtnOn = new Array;
var menuBtnOff = new Array;

function Preload()
{
	for (var i = 1; i <= 8; i++) {
		menuBtnOn[i] = new Image;
		menuBtnOn[i].src = 'img/menu/menu' + i + '_on.jpg';
		menuBtnOff[i] = new Image;
		menuBtnOff[i].src = 'img/menu/menu' + i + '_off.jpg';
	}
}

function menuOn(num)
{
	document.images['menu' + num].src = menuBtnOn[num].src;
}

function menuOff(num)
{
	document.images['menu' + num].src = menuBtnOff[num].src;
}

Preload();