function toggleLayer(layerName) {
	if ( (document.all && document.all[layerName].style.display == "block") 
		|| document.getElementById(layerName).style.display == "block")
	{
		hideLayer(layerName);
	} else {
		showLayer(layerName);
	}
}

function showLayer(layerName)
{
	if(document.all)
	{
		document.all[layerName].style.display = "block";
		document.all[layerName].style.visibility = "visible";
	}
	else
	{
		document.getElementById(layerName).style.display = "block";
		document.getElementById(layerName).style.visibility = "visible";
	}
}	

function hideLayer(layerName)
{
	if(document.all)
	{
		document.all[layerName].style.display = "none";
	}
	else
	{
		document.getElementById(layerName).style.display = "none";
		document.getElementById(layerName).style.visibility = "hidden";
	}
}