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

var timerID;
var libraryOptions = "libraryOptions";

function reveal(menu, parent) {
  if (document.layers) {
    daMenu = document.layers[menu];
  }
  else {
    daMenu = document.getElementById(menu).style;
  }

    daMenu.visibility = "visible";
//  lastMenu = daMenu;
}

function hideMenu(menu, parent) {
  if (document.layers) {
    daMenu = document.layers[menu];
  }
  else {
    daMenu = document.getElementById(menu).style;
  }
  
  daMenu.visibility = "hidden";
}

function menuItem(item){
  if (document.layers) {
    daLast = document.layers[lastItem];
    daItem = document.layers[item];
  } else if (document.all) {
    daLast = document.all(lastItem).style;
    daItem = document.all(item).style;
  }
  daLast.visibility = "hidden";
  daItem.visibility = "visible";
  lastMenu.visibility = "hidden";
  lastItem = item;
}