var oldLayer;
function archiveLayerSwitch(layerName) {
	// Hide the last layer displayed
	if(document.getElementById(oldLayer) && oldLayer != layerName) {
		document.getElementById(oldLayer).className = "archiveHidden";
	}
	// Store the layer for next time
	oldLayer = layerName;
	// Hide or display the new layer
	if(document.getElementById(layerName)) {
		if(document.getElementById(layerName).className == "archiveVisible") {
			document.getElementById(layerName).className = "archiveHidden";
		} else {
			document.getElementById(layerName).className = "archiveVisible";
		}
	}
}