Dropdowns

Toggle contextual overlays for displaying lists of links and more with the Bootstrap dropdown plugin.

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 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.

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.

How to use

Dropdowns can be triggered from <a>or <button> elements.. Create a element with .dropdown class, or another element that declares position: relative; and add the dropdown's toggle (your button or link) with .dropdown-toggle class and the dropdown menu element within. The dropdown menu element (.dropdown-menu) contains list of menu contents added with .dropdown-item class.

With Button

Create a <button> element and add .dropdown-toggle class

With Link

And with <a> elements:

You can do dropdown menu with any button variant.

Split button

Create split button dropdowns with the addition of .dropdown-toggle-split.

Sizing

Vary the size of the button dropdowns .btn-lg and .btn-sm. It also works with split dropdown buttons.

Directions

You can trigger dropdown menu in four directions.

Dropup

Adding .dropup to the parent element will trigger dropdown menus above the <a>or <button> elements.

Dropright

Adding .dropright to the parent element will trigger dropdown menus right of the <a>or <button> elements.

Dropleft

Adding .dropright to the parent element will trigger dropdown menus at the left of the <a>or <button> elements.

Menu items

Dropdown menu contents can be <a> or <button> elements.

You can also create non-interactive dropdown items with .dropdown-item-text.

Active

Add .active to items in the dropdown which applies active style.

Disabled

Add .disabled to items in the dropdown which applies disabled style.

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.

Menu content
Headers

Add a header sections in dropdown menu using .dropdown-header.

Dividers

Separate groups of related menu items with a divider using .dropdown-divider.

Text

You can add any plain text within a dropdown menu with text and use spacing utilities. You can set the menu using custom styling(inline styles or css).

Forms

You can also put a form within a dropdown menu, or make a form itself into a dropdown menu and use margin or padding utilities to give it the negative space you require.

Dropdown options

To change the location of the dropdown use data-offset or data-reference.

Usage
Via data attributes

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

Via JavaScript

Call the dropdowns via JavaScript:

$('.dropdown-toggle').dropdown()
data-toggle="dropdown" still required

Even when you call your dropdown via JavaScript or instead use the data-api, data-toggle="dropdown" is always required on the dropdown's trigger element.

Options

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

Name Type Default Description
offset number | string | function 0 Offset of the dropdown relative to its target. For more information refer to Popper.js's offset docs.
flip boolean true Allow Dropdown to flip in case of an overlapping on the reference element. For more information refer to Popper.js's flip docs.
boundary string | element 'scrollParent' Overflow constraint boundary of the dropdown menu. Accepts the values of 'viewport', 'window', 'scrollParent', or an HTMLElement reference (JavaScript only). For more information refer to Popper.js's preventOverflow docs.
reference string | element 'toggle' Reference element of the dropdown menu. Accepts the values of 'toggle', 'parent', or an HTMLElement reference. For more information refer to Popper.js's referenceObject docs.
display string 'dynamic' By default, we use Popper.js for dynamic positioning. Disable this with static.

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

Methods
Method Description
$().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. hide.bs.dropdown and hidden.bs.dropdown events have a clickEvent property (only when the original event type is click) that contains an Event Object for the click event.

Event Description
show.bs.dropdown This event fires immediately when the show instance method is called.
shown.bs.dropdown This event is fired when the dropdown has been made visible to the user (will wait for CSS transitions, to complete).
hide.bs.dropdown This event is fired immediately when the hide instance method has been called.
hidden.bs.dropdown This event is fired when the dropdown has finished being hidden from the user (will wait for CSS transitions, to complete).
$('#myDropdown').on('show.bs.dropdown', function () {
  // do something…
})
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