function tw_toggle(div_id) {
  style = document.getElementById(div_id).style;

  if (style.display == "none") {
    style.display = "";
  }
  else {
    style.display = "none";
  }
}

function tw_expand_class(class_name) {
  nodes = document.getElementsByClassName(class_name);
  for (i=0; i < nodes.length; i++) {
    nodes[i].style.display = "";
  }
}