<div class="dropdown">
    <button class="btn btn-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-haspopup="true">
        Dropdown button
    </button>
    <div class="dropdown-menu">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
    </div>
</div>

<div class="dropdown show">
    <a class="btn btn-secondary dropdown-toggle" href="#" role="button" data-toggle="dropdown" aria-haspopup="true">
        Dropdown link
    </a>
    <div class="dropdown-menu">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
    </div>
</div>


<div class="dropdown show">
    <a class="btn btn-primary dropdown-toggle" href="#" role="button" data-toggle="dropdown" aria-haspopup="true">
        Dropdown link
    </a>

    <div class="dropdown-menu">
        <a class="dropdown-item" href="#">Regular link</a>
        <a class="dropdown-item active" href="#">Active link</a>
        <a class="dropdown-item" href="#">Another link</a>
    </div>
</div>

Disabled Menu Items Dropdowns


<div class="dropdown show">
    <a class="btn btn-primary dropdown-toggle" href="#" role="button" data-toggle="dropdown" aria-haspopup="true">
        Dropdown link
    </a>

    <div class="dropdown-menu">
        <a class="dropdown-item" href="#">Regular link</a>
        <a class="dropdown-item disabled" href="#">Disabled link</a>
        <a class="dropdown-item" href="#">Another link</a>
    </div>
</div>