layerRef = ""
	styleRef = ""

	if (navigator.appName == "Netscape")
	{
		layerRef = ".layers"
		styleRef = ""
	}
	else //must be IE
	{
		layerRef = ".all"
		styleRef = ".style"
	}


	function mostraLayer(layerName)
	{
	eval("document" + layerRef + "[layerName]" + styleRef + ".visibility = 'visible'")
		//document.all[layerName].style.visibility = 'visible'
	}
	function nascondiLayer(layerName)
	{
	eval("document" + layerRef + "[layerName]" + styleRef + ".visibility = 'hidden'")
	//document.all[layerName].style.visibility = 'hidden'	
	}