<div class="input-group">
<div class="input-group-prepend">
<button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dropdown</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with dropdown button">
</div>
