// Hide/show layers function
function showLayer(id)
{
	var x = document.getElementById ('layer_'+id);
	if (x.style.display != 'none') {
		x.style.visibility = "hidden";
		x.style.display = "none";
		document['layer_img_'+id].src = "images/arrow_right.gif";
		
	}
	else
	{
		x.style.visibility = "visible";
		x.style.display = "block";
		document['layer_img_'+id].src = "images/arrow_bottom.gif";		
	}
}