function clearall() {
  if (document.layers) {
    document.Home.visibility = "hidden";
    document.AboutUs.visibility = "hidden";
    document.HYCOM.visibility = "hidden";
    document.DataServer.visibility = "hidden";
    document.Global.visibility = "hidden";
    document.Basin.visibility = "hidden";
    document.Regional.visibility = "hidden";
    document.ProcessStudies.visibility = "hidden";
    document.DataAssimilation.visibility = "hidden";
    document.Reanalysis.visibility = "hidden";
    document.OceanPrediction.visibility = "hidden";
    document.Miscellanea.visibility = "hidden";
    document.Outreach.visibility = "hidden";
    document.Publications.visibility = "hidden";
    document.Meetings.visibility = "hidden";
    document.Forums.visibility = "hidden";
    document.ExternalLinks.visibility = "hidden";
    document.ContactInfo.visibility = "hidden";
    document.MailingList.visibility = "hidden";
  }
  else if(document.all) {
    document.all.Home.style.visibility = "hidden";
    document.all.AboutUs.style.visibility = "hidden";
    document.all.HYCOM.style.visibility = "hidden";
    document.all.DataServer.style.visibility = "hidden";
    document.all.Global.style.visibility = "hidden";
    document.all.Basin.style.visibility = "hidden";
    document.all.Regional.style.visibility = "hidden";
    document.all.ProcessStudies.style.visibility = "hidden";
    document.all.DataAssimilation.style.visibility = "hidden";
    document.all.Reanalysis.style.visibility = "hidden";
    document.all.OceanPrediction.style.visibility = "hidden";
    document.all.Miscellanea.style.visibility = "hidden";
    document.all.Outreach.style.visibility = "hidden";
    document.all.Publications.style.visibility = "hidden";
    document.all.Meetings.style.visibility = "hidden";
    document.all.Forums.style.visibility = "hidden";
    document.all.ExternalLinks.style.visibility = "hidden";
    document.all.ContactInfo.style.visibility = "hidden";
    document.all.MailingList.style.visibility = "hidden";
  }
  else {
    document.getElementById('Home').style.visibility = "hidden";
    document.getElementById('AboutUs').style.visibility = "hidden";
    document.getElementById('HYCOM').style.visibility = "hidden";
    document.getElementById('DataServer').style.visibility = "hidden";
    document.getElementById('Global').style.visibility = "hidden";
    document.getElementById('Basin').style.visibility = "hidden";
    document.getElementById('Regional').style.visibility = "hidden";
    document.getElementById('ProcessStudies').style.visibility = "hidden";
    document.getElementById('DataAssimilation').style.visibility = "hidden";
    document.getElementById('Reanalysis').style.visibility = "hidden";
    document.getElementById('OceanPrediction').style.visibility = "hidden";
    document.getElementById('Miscellanea').style.visibility = "hidden";
    document.getElementById('Outreach').style.visibility = "hidden";
    document.getElementById('Publications').style.visibility = "hidden";
    document.getElementById('Meetings').style.visibility = "hidden";
    document.getElementById('Forums').style.visibility = "hidden";
    document.getElementById('ExternalLinks').style.visibility = "hidden";
    document.getElementById('ContactInfo').style.visibility = "hidden";
    document.getElementById('MailingList').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;
}