Event.observe(document, 'dom:loaded', function() {
	// set up images
	var bgIms = $('background-images').select('div');
	var curIm = 0;

	if (bgIms.length) {
		bgIms.invoke('setStyle', { 'zIndex': 1 });
		bgIms[curIm].setStyle({ 'zIndex': 3 });

		function tick() {
			var newCurIm = curIm + 1;
			if (newCurIm >= bgIms.length)
				newCurIm = 0;

			bgIms[newCurIm].setStyle({ 'zIndex': 2 });
			bgIms[curIm].fade({afterFinish: function() {
				bgIms[newCurIm].setStyle({ 'zIndex': 3 });
				bgIms[curIm].setStyle({ 'display': 'block', 'zIndex': 1 });
				curIm = newCurIm;
				setTimeout(tick, 5000);
			}});
		}

		setTimeout(tick, 5000);
	}
});