function showLayer (id) {
	if (!document.getElementById) 
		return;		

	hideLayers ();

	var oLayer = document.getElementById ("Popup"+id);
	oLayer.style.visibility="visible";
}

function hideLayers () {
	if (!document.getElementById) 
		return;		

	for (var i = 1; i <= iLayers; i++) {		
		var oLayer = document.getElementById ("Popup"+i);
		oLayer.style.visibility="hidden";
	}
}