o arguments hold the groups of which the positions are to be swapped and the third argument holds the DataSet with all groups.
      </td>
    </tr>

    <tr>
      <td>groupTemplate</td>
      <td>function</td>
      <td>none</td>
      <td>A template function used to generate the contents of the groups. The function is called by the Timeline with a groups data as the first argument and the group element as the second, and must return HTML code, a string or a template as result. When the option groupTempla