var undef;
var active_item = undef;
var top_items = [];
var sub_container = [];

function display_item(item) {
  reset_items();
  if (active_item != item) {
    item.className = 'active';
    var sub = get_sub_container(item.parentNode);
    if (sub) {
      sub.style.display = 'block';
    }
  }
  if (active_item == item) {
    item.className = '';
  }
  active_item = item;
}

function reset_items() {
  if (! top_items.length) {
    set_top_items();
  }
  for (var i=0; i<top_items.length; i++) {
    var item = top_items[i];
    item.className = '';
    var sub = get_sub_container(item.parentNode);
    if (sub) {
      sub.style.display = 'none';
    }
  }
  return;
}

function set_top_items() {
  var arr = document.getElementsByTagName('a');
  for (var i=0; i<arr.length; i++) {
    var item = arr[i];
    if (! item.parentNode.parentNode.parentNode.id == 'navigation') {
      continue;
    }
    top_items.push(item);
  }
  return;
}

function get_sub_container(item) {
  if (! item) {
    return false;
  }
  if (! sub_container.length) {
    set_sub_container();
  }
  for (var i=0; i<sub_container.length; i++) {
    var sub = sub_container[i];
    if (sub.parentNode != item) {
      continue;
    }
    return sub;
  }
  return false;
}

function set_sub_container() {
  sub_container = document.getElementsByTagName('ul');
}

function set_active_item() {
  var id = parent.top.active_nav;
  if (! id) {
    return;
  }
  var idx = id.split('-')[0];
  if (! idx) {
    return;
  }
  var item = document.getElementById(idx);
  if(! item) {
    return;
  }
  display_item(item);
}