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>