ut to be removed. The signature and semantics are the same as for <code>onRemove</code>.
      </td>
    </tr>
    
    <tr>
      <td>onUpdate</td>
      <td>function</td>
      <td>none</td>
      <td>Callback function triggered when an item is about to be updated, when the user double taps an item in the Timeline. See section <a href="#Editing_Items">Editing Items</a> for more information. Only applicable when both options <code>selectable</code> and <code>editable.updateTime</code> or <code>editable.upd