//----------- Cross-Browser Layer Targeting -----------

function getLayer(layerName, layerUp) {
  var layer;
  if (n4) {
  	if(layerUp){
	return(document.layers[0].layers[layerUp].layers[layerName]);
	} else {
    return(document.layers[0].layers[layerName]);
	}
 } else if (i4) {
    return eval('document.all.' + layerName + '.style');
  } else if (ie || ns) {
    return document.getElementById(layerName);
  } else {
    return(null);
  }
}

//----------- Layer Visibility -----------

function showLayer(layerName) {
  
  var layer = getLayer(layerName);
  if (n4) {
    layer.visibility = "show";
  } else if (i4) {
    layer.visibility = "visible";
  } else if (ie || ns) {
    layer.style.visibility = "visible";
  }
}

//----------- Layer Invisibility -----------

function hideLayer(layerName) {
		
  var layer = getLayer(layerName);
  if (n4) {
    layer.visibility = "hide";
  } else if (i4) {
    layer.visibility = "hidden";
  } else if (ie || ns) {
    layer.style.visibility = "hidden";
  }
}