I need to set the selected item of my dropdown-menu in jquery but I can't make it work.

My dropdown code looks as follows:

```
<button type="button" id="aktiv" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-expanded="false">
  Aktiv <span class="caret"></span>
</button>
<ul class="dropdown-menu" role="menu">
 <li><a href="#">Aktiv</a></li>
 <li><a href="#">Inaktiv</a></li>
</ul>

```