function revealLayer(imageId)
{
	image = document.getElementById(imageId);
	setOpacity(image, 0);
	image.style.visibility = "visible";
	fadeIn(imageId,0);
}

function obscureLayer(imageId)
{
	image = document.getElementById(imageId);
	setOpacity(image, 100);
	image.style.visibility = "visible";
	fadeOut(imageId,100);
}

function fadeIn(objId, opacity)
{
	if (document.getElementById)
	{
		obj = document.getElementById(objId);

		if (opacity <= 100)
		{
			setOpacity(obj, opacity);
			opacity += 20;
			window.setTimeout("fadeIn('"+objId+"',"+opacity+")", 100);
		}
	}
}

function fadeOut(objId, opacity)
{
	if (document.getElementById)
	{
		obj = document.getElementById(objId);

		if (opacity >= 0)
		{
			setOpacity(obj, opacity);
			opacity -= 20;
			window.setTimeout("fadeOut('"+objId+"',"+opacity+")", 100);
		}
		else { obj.style.visibility = "hidden"; }
	}
}

function setOpacity(obj, opacity)
{
	opacity = (opacity == 100)?99.999:opacity;

	// IE/Win
	obj.style.filter = "alpha(opacity:"+opacity+")";

	// Safari<1.2, Konqueror
	obj.style.KHTMLOpacity = opacity/100;

	// Older Mozilla and Firefox
	obj.style.MozOpacity = opacity/100;

	// Safari 1.2, newer Firefox and Mozilla, CSS3
	obj.style.opacity = opacity/100;
}

function runLayers(x, i, l)
{
	if (i <= l)
	{
		revealLayer(document.getElementById('L'+i).id);
		i++;
	}
	else
	{
		for (n=1 ; n <= l ; n++) { obscureLayer(document.getElementById('L'+n).id); }
		i = 1;
	}

	window.setTimeout("runLayers('" + x + "'," + i + "," + l + ")", 5000);
}