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.

Dropdowns are built on a third party library, Popper.js, 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 standard defines an actual role="menu" widget, 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 <a> or <button> elements to better fit your potential needs.

Single button

Any single .btn can be turned into a dropdown toggle with some markup changes. Here's how you can put them to work with either <button> elements:

{% capture example %}

And with <a> elements:

{% capture example %}

The best part is you can do this with any button variant, too:

{% highlight html %}

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 %}

Sizing

Button dropdowns work with buttons of all sizes, including default and split dropdown buttons.

{% highlight html %}

Directions

Dropup

Trigger dropdown menus above elements by adding .dropup to the parent element.

{% highlight html %}

Dropright

Trigger dropdown menus at the right of the elements by adding .dropright to the parent element.

{% highlight html %}

Dropleft

Trigger dropdown menus at the left of the elements by adding .dropleft to the parent element.

{% highlight html %}

Menu items

Historically dropdown menu contents had to be links, but that's no longer the case with v4. Now you can optionally use <button> elements in your dropdowns instead of just <a>s.

{% capture example %}

You can also create non-interactive dropdown items with .dropdown-item-text. Feel free to style further with custom CSS or text utilities.

{% capture example %}

Active

Add .active to items in the dropdown to style them as active.

{% capture example %}

Disabled

Add .disabled to items in the dropdown to style them as disabled.

{% capture example %}

Menu alignment

By default, a dropdown menu is automatically positioned 100% from the top and along the left side of its parent. Add .dropdown-menu-right to a .dropdown-menu to right align the dropdown menu.

{% capture callout %} Heads up! Dropdowns are positioned thanks to Popper.js (except when they are contained in a navbar). {% endcapture %} {% include callout.html content=callout type=“info” %}

{% capture example %}

Menu content

Headers

Add a header to label sections of actions in any dropdown menu.

{% capture example %}

Dividers

Separate groups of related menu items with a divider.

{% capture example %}

Text

Place any freeform text within a dropdown menu with text and use [spacing utilities]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/spacing/). Note that you'll likely need additional sizing styles to constrain the menu width.

{% capture example %}

Forms

Put a form within a dropdown menu, or make it into a dropdown menu, and use [margin or padding utilities]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/spacing/) to give it the negative space you require.

{% capture example %}

{% capture example %}

Dropdown options

Use data-offset or data-reference to change the location of the dropdown.

{% capture example %}

Usage

Via data attributes or JavaScript, the dropdown plugin toggles hidden content (dropdown menus) by toggling the .show class on the parent list item. The data-toggle="dropdown" attribute is relied on for closing dropdown menus at an application level, so it's a good idea to always use it.

{% capture callout %} On touch-enabled devices, opening a dropdown adds empty ($.noop) mouseover handlers to the immediate children of the <body> element. This admittedly ugly hack is necessary to work around a quirk in iOS' event delegation, which would otherwise prevent a tap anywhere outside of the dropdown from triggering the code that closes the dropdown. Once the dropdown is closed, these additional empty mouseover handlers are removed. {% endcapture %} {% include callout.html content=callout type=“info” %}

Via data attributes

Add data-toggle="dropdown" to a link or button to toggle a dropdown.

{% highlight html %}

Via JavaScript

Call the dropdowns via JavaScript:

{% highlight js %} $(‘.dropdown-toggle’).dropdown() {% endhighlight %}

{% capture callout %}

data-toggle="dropdown" still required

Regardless of whether you call your dropdown via JavaScript or instead use the data-api, data-toggle="dropdown" is always required to be present on the dropdown's trigger element. {% endcapture %} {% include callout.html content=callout type=“info” %}

Options

Options can be passed via data attributes or JavaScript. For data attributes, append the option name to data-, as in data-offset="".

Note when boundary is set to any value other than 'scrollParent', the style position: static is applied to the .dropdown container.

Methods

MethodDescription
$().dropdown('toggle')Toggles the dropdown menu of a given navbar or tabbed navigation.
$().dropdown('update')Updates the position of an element's dropdown.
$().dropdown('dispose')Destroys an element's dropdown.

Events

All dropdown events are fired at the .dropdown-menu's parent element and have a relatedTarget property, whose value is the toggling anchor element.

EventDescription
show.bs.dropdownThis event fires immediately when the show instance method is called.
shown.bs.dropdownThis event is fired when the dropdown has been made visible to the user (will wait for CSS transitions, to complete).
hide.bs.dropdownThis event is fired immediately when the hide instance method has been called.
hidden.bs.dropdownThis event is fired when the dropdown has finished being hidden from the user (will wait for CSS transitions, to complete).

{% highlight js %} $(‘#myDropdown’).on(‘show.bs.dropdown’, function () { // do something… }) {% endhighlight %}