function toggleLayer(layerName)
{
	var object = null;
	if (document.getElementById && document.getElementById(layerName) != null)
	{
		if (document.getElementById(layerName).style.display == "block")
			document.getElementById(layerName).style.display = "none";
		else
			document.getElementById(layerName).style.display = "block";
	}
	else if (document.layers && document.layers[layerName] != null)
	{
		if (document.layers[layerName].display == "block")
			document.layers[layerName].display = "none";
		else
			document.layers[layerName].display == "block";		
	}
	else if (document.all)
	{
		if(document.all[layerName].style.display == "block")
			document.all[layerName].style.display = "none";
		else
			document.all[layerName].style.display = "block";
	}
	
}