--- layout: docs title: Dropdowns description: Toggle contextual overlays for displaying lists of links and more with the Bootstrap dropdown plugin. group: components toc: true --- ## Overview Dropdowns are toggleable, contextual overlays for displaying lists of links and more. They're made interactive with the included Bootstrap dropdown JavaScript plugin. They're toggled by clicking, not by hovering; this is [an intentional design decision](https://markdotto.com/2012/02/27/bootstrap-explained-dropdowns/). Dropdowns are built on a third party library, [Popper.js](https://popper.js.org/), which provides dynamic positioning and viewport detection. Be sure to include [popper.min.js]({{ site.cdn.popper }}) before Bootstrap's JavaScript or use `bootstrap.bundle.min.js` / `bootstrap.bundle.js` which contains Popper.js. Popper.js isn't used to position dropdowns in navbars though as dynamic positioning isn't required. If you're building our JavaScript from source, it [requires `util.js`]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/javascript/#util). ## Accessibility The [WAI ARIA](https://www.w3.org/TR/wai-aria/) standard defines an actual [`role="menu"` widget](https://www.w3.org/WAI/PF/aria/roles#menu), but this is specific to application-like menus which trigger actions or functions. ARIA menus can only contain menu items, checkbox menu items, radio button menu items, radio button groups, and sub-menus. Bootstrap's dropdowns, on the other hand, are designed to be generic and applicable to a variety of situations and markup structures. For instance, it is possible to create dropdowns that contain additional inputs and form controls, such as search fields or login forms. For this reason, Bootstrap does not expect (nor automatically add) any of the `role` and `aria-` attributes required for true ARIA menus. Authors will have to include these more specific attributes themselves. However, Bootstrap does add built-in support for most standard keyboard menu interactions, such as the ability to move through individual `.dropdown-item` elements using the cursor keys and close the menu with the ESC key. ## Examples Wrap the dropdown's toggle (your button or link) and the dropdown menu within `.dropdown`, or another element that declares `position: relative;`. Dropdowns can be triggered from `` or ` {% endcapture %} {% include example.html content=example %} And with `` elements: {% capture example %} {% endcapture %} {% include example.html content=example %} The best part is you can do this with any button variant, too: {% highlight html %}

{% endhighlight %} ### Split button Similarly, create split button dropdowns with virtually the same markup as single button dropdowns, but with the addition of `.dropdown-toggle-split` for proper spacing around the dropdown caret. We use this extra class to reduce the horizontal `padding` on either side of the caret by 25% and remove the `margin-left` that's added for regular button dropdowns. Those extra changes keep the caret centered in the split button and provide a more appropriately sized hit area next to the main button.

{% highlight html %}

{% endhighlight %} ## Sizing Button dropdowns work with buttons of all sizes, including default and split dropdown buttons.

{% highlight html %}