bootstrap dropdown select
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenu2">
<button class="dropdown-item" type="button">Action</button>
<button class="dropdown-item" type="button">Another action</button>
<button class="dropdown-item" type="button">Something else here</button>
</div>
</div>