function toggleLayer(layer)
{
	if (layer != "layerAppFltrs" && objectById("layerAppFltrs")) objectById("layerAppFltrs").style.display = "none";
	if (layer != "layerRefine" && objectById("layerRefine")) objectById("layerRefine").style.display = "none";
	if (layer != "layerSort" && objectById("layerSort")) objectById("layerSort").style.display = "none";

	// set the active layer to visible
	objectById(layer).style.display = "";
	
	// check if the class needs to be switched for the last active layer (e.g. if it's the last one it will need to switch classes to show the right background image for the header)
	if (layer == "layerSort" && objectById("layerSort"))
	{
		objectById("toggleSort").className = objectById("toggleSort").className.replace("last", "");
	}
	else if (objectById("layerSort"))
	{
		if (objectById("toggleSort").className.indexOf("last") < 0) objectById("toggleSort").className += " last";
	}
}