function preload(i) { 
	var img = new Image(); 
	img.src = i; return img; 
}

preload('/images/menu/about-a.gif');
preload('/images/menu/agent-a.gif');
preload('/images/menu/business-a.gif');
preload('/images/menu/weather-a.gif');
preload('/images/menu/club-a.gif');
preload('/images/menu/gallery-a.gif');


function roll(name, mode) {
	if ( mode == 'on' ) m = '-a'; else m = '';
	window.document.images[name].src = '/images/menu/' + name + m + '.gif';
}