Drop-downs are toggle able, contextual overlays for displaying lists of links and more
<div class="btn-group">
<button type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown <span class="caret"></span>
</button>
<ul class="dropdown-menu">
<li class="dropdown-item"><a href="javascript:;">Action</a></li>
<li class="dropdown-item"><a href="javascript:;">Another action</a></li>
<li class="dropdown-item"><a href="javascript:;">Something else here</a></li>
<li class="dropdown-item"><a href="javascript:;">Separated link</a></li>
</ul>
</div>
