/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Function:		mapLayerOn(layer)
Description:	Turns on specified layer(s)
Arguments:		none
Return:			
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function mapLayerOn(layerNames){
	var myMap = getMap(); 
	myMap.setAutoRefresh(false);
	layers = layerNames.split(",");
	myMap.setAutoRefresh(false);
	var refresh=false;
	for (i=0; i<layers.length; i++){
		var myLayer = myMap.getMapLayer(layers[i]);
		if (!myLayer.getVisibility()){
			refresh=true;
			myLayer.setVisibility(true);
		}
		myLayer.setVisibility(true);
	}
	myMap.setAutoRefresh(true);
	if(refresh){
		myMap.refresh();
	}
}