function ttoggle(link, id)
{
  var element = document.getElementById(id);
  if (element.style.display == 'none')
  {
    element.style.display = 'block';
    link.className = 'boxdown';
  }
  else if (element.style.display == 'block')
  {
    element.style.display = 'none';
    link.className = 'boxup';
  }
}