function vnav_mouseover(name, desc)
{
  document.images[name].src = "images/" + name + "_a.gif";
  window.status = desc;
}

function vnav_mouseout(name)
{
  document.images[name].src = "images/" + name + ".gif";
  window.status = "";
}

function vnav_setcurrent(name)
{
  if (document.images[name] != null) {
    document.images[name].src = "images/" + name + "_c.gif";
  }
}