function toggleDiv(divName) 
{
  thisDiv = document.getElementById(divName);
  if (thisDiv) 
  {
    if (thisDiv.style.display == "none")
    {
      thisDiv.style.display = "block";
    }
    else
    {
      thisDiv.style.display = "none";
    }
  }
  else
  {
    alert("Error: Could not locate div with id: " + divName);
  }
}