function hideLayer(layer) {

  if (NS4)
    layer.visibility = "hide";
  if (IE4)
    layer.style.visibility = "hidden";
}

function showLayer(layer) {

  if (NS4)
    layer.visibility = "show";
  if (IE4)
    layer.style.visibility = "visible";
}

//-----------------------------------------------------------------------------
// Layer utilities.
//-----------------------------------------------------------------------------

function getLayer(name) {

  if (NS4)
    return findLayer(name, document);
  if (IE4)
    return eval('document.all.' + name);
  return null;
}

function findLayer(name, doc) {

  var i, layer;

  for (i = 0; i < doc.layers.length; i++) {
    layer = doc.layers[i];
    if (layer.name == name)
      return layer;
    if (layer.document.layers.length > 0)
      if ((layer = findLayer(name, layer.document)) != null)
        return layer;
  }
  return null;
}