rties]
  }
  // more groups...
]);
</pre>


  <p>
    Groups can have the following properties:
  </p>

  <table class="properties">
    <tr>
      <th>Name</th>
      <th>Type</th>
      <th>Required</th>
      <th>Description</th>
    </tr>
    <tr>
      <td>className</td>
      <td>String</td>
      <td>no</td>
      <td>This field is optional. A className can be used to give groups
        an individual css style. For example, when a group has className
        'red', one can define a css style
       