function clearall() {
  if (document.layers) {
    document.Home.visibility = "hidden";
    document.Biography.visibility = "hidden";
    document.ResearchInterests.visibility = "hidden";
    document.Publications.visibility = "hidden";
    document.LAPCOD.visibility = "hidden";
    document.OceanCurrents.visibility = "hidden";
    document.SourceCode.visibility = "hidden";
    document.DataSets.visibility = "hidden";
    document.PhotoGallery.visibility = "hidden";
    document.ContactInfo.visibility = "hidden";
  }
  else if(document.all) {
    document.all.Home.style.visibility = "hidden";
    document.all.Biography.style.visibility = "hidden";
    document.all.ResearchInterests.style.visibility = "hidden";
    document.all.Publications.style.visibility = "hidden";
    document.all.LAPCOD.style.visibility = "hidden";
    document.all.OceanCurrents.style.visibility = "hidden";
    document.all.SourceCode.style.visibility = "hidden";
    document.all.DataSets.style.visibility = "hidden";
    document.all.PhotoGallery.style.visibility = "hidden";
    document.all.ContactInfo.style.visibility = "hidden";
  }
  else {
    document.getElementById('Home').style.visibility = "hidden";
    document.getElementById('Biography').style.visibility = "hidden";
    document.getElementById('ResearchInterests').style.visibility = "hidden";
    document.getElementById('Publications').style.visibility = "hidden";
    document.getElementById('LAPCOD').style.visibility = "hidden";
    document.getElementById('OceanCurrents').style.visibility = "hidden";
    document.getElementById('SourceCode').style.visibility = "hidden";
    document.getElementById('DataSets').style.visibility = "hidden";
    document.getElementById('PhotoGallery').style.visibility = "hidden";
    document.getElementById('ContactInfo').style.visibility = "hidden";
  }
}

function hide(id) {
  if (document.layers && document.layers[id] != null) {
    document.layers[id].visibility='hidden';
  }
  else if (document.all) {
    document.all[id].style.visibility='hidden';
  }
  else {
    document.getElementById(id).style.visibility='hidden';
  }
}

function show(id) {
  clearall();
  if (document.layers) {
    document.layers[id].visibility='visible';
  }
  else if (document.all) {
    document.all[id].style.visibility='visible';
  }
  else {
    document.getElementById(id).style.visibility='visible';
  }
}

function showLayer(id) {
  clearall();
  if (document.layers) {
    document.layers[id].visibility='visible';
  }
  else if (document.all) {
    document.all[id].style.visibility='visible';
  }
  else {
    document.getElementById(id).style.visibility='visible';
  }
}

// called when page is done loading, enables layer show/hides
function beenThere() {
  loaded = true;
}