function showHideContent(id)
  {
    var elem = document.getElementById("D" + id);
    var image = document.getElementById("I" + id);
    if (elem)
    {
      if (elem.style.visibility != 'visible')
      {

	if (image != null) image.src = "images/minus_sign.gif";
        elem.style.display = 'block';
        elem.style.visibility = 'visible';
      }
      else
      {
	if (image != null) image.src = "images/plus_sign.gif";
        elem.style.display = 'none';
        elem.style.visibility = 'hidden';
      }
    }
  }