oupCount; g++) {
    groups.add({id: g, content: names[g]});
  }

  // create a dataset with items
  var items = new vis.DataSet();
  for (var i = 0; i < itemCount; i++) {
    var start = now.clone().add(Math.random() * 200, 'hours');
    var group = Math.floor(Math.random() * groupCount);
    items.add({
      id: i,
      group: group,
      content: 'item ' + i +
          ' <span style="color:#97B0F8;">(' + names[group] + ')</span>',
      start: start,
      type: 'box'
    });
  }

  // create visuali