var activeLayer = "content0";

function SwapLayer (layername) {

	if (activeLayer.length > 0) {
		//document.getElementById(activeLayer).style.visibility = "hidden";
		document.getElementById(activeLayer).style.display = "none";
	}

	if (layername.length > 0) {
		//document.getElementById(layername).style.visibility = "visible";
		document.getElementById(layername).style.display = "block";
		activeLayer = layername;
	}

}