if (document.layers) {
  visible = 'show';
  hidden = 'hide';
} else if (document.all) {
  visible = 'visible';
  hidden = 'hidden';
}

function barHide(menu) {
  if (document.layers) {
    daMenu = document.layers[menu];
  } else if (document.all) {
    daMenu = document.all(menu).style;
  }

    daMenu.visibility = hidden;
    lastMenu = daMenu;
}

function barShow(menu) {
  if (document.layers) {
    daMenu = document.layers[menu];
  } else if (document.all) {
    daMenu = document.all(menu).style;
  }

    daMenu.visibility = visible;
    lastMenu = daMenu;
}