function toggleVisibility(titleId, divId) {
  var title = document.getElementById(titleId);
  var div = document.getElementById(divId);
  if (div.style.display == 'block') {
    div.style.display = 'none';
    title.getElementsByTagName('img')[0].src = 'expand.gif';
  } else {
    title.getElementsByTagName('img')[0].src = 'collapse.gif';
    div.style.display = 'block';
    div.getElementsByTagName('a')[0].style.display = 'block';
  }
}