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. Theyre made interactive with the included Bootstrap dropdown JavaScript plugin. Theyre 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 Bootstraps JavaScript or use bootstrap.bundle.min.js / bootstrap.bundle.js which contains Popper.js. Popper.js isnt used to position dropdowns in navbars though as dynamic positioning isnt required.
If youre 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.
Bootstraps 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 dropdowns toggle [your button or link] and the dropdown menu within .dropdown, or another element that declares position: relative;. Dropdowns can be triggered from Action Another action Something else here
And with Dropdown link
Action Another action Something else here
The best part is you can do this with any button variant, too: Primary Action Another action Something else here Separated link Secondary Action Another action Something else here Separated link Success Action Another action Something else here Separated link Info Action Another action Something else here Separated link Warning Action Another action Something else here Separated link Danger Action Another action Something else here Separated link
Action
Action Another action Something else here
Separated link
Split button dropdowns
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 thats 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. Primary Toggle Dropdown Action Another action Something else here Separated link Secondary Toggle Dropdown Action Another action Something else here Separated link Success Toggle Dropdown Action Another action Something else here Separated link Info Toggle Dropdown Action Another action Something else here Separated link Warning Toggle Dropdown Action Another action Something else here Separated link Danger Toggle Dropdown Action Another action Something else here Separated link
Action
Toggle Dropdown Action Another action Something else here
Separated link
Sizing
Button dropdowns work with buttons of all sizes, including default and split dropdown buttons. Large button Action Another action Something else here Separated link Large split button Toggle Dropdown Action Another action Something else here Separated link Small button Action Another action Something else here Separated link Small split button Toggle Dropdown Action Another action Something else here Separated link
Large split button
Toggle Dropdown ...
Small split button
Toggle Dropdown ...
Dropup variation
Trigger dropdown menus above elements by adding .dropup to the parent element. Dropup Action Another action Something else here Separated link Split dropup Toggle Dropdown Action Another action Something else here Separated link
Split dropup
Toggle Dropdown
Dropright variation
Trigger dropdown menus at the right of the elements by adding .dropright to the parent element. Dropright Action Another action Something else here Separated link Split dropright Toggle Dropdright Action Another action Something else here Separated link
Split dropright
Toggle Dropright
Dropleft variation
Trigger dropdown menus at the left of the elements by adding .dropleft to the parent element. Dropleft Action Another action Something else here Separated link Toggle Dropleft Action Another action Something else here Separated link Split dropleft
Menu items
Historically dropdown menu contents had to be links, but thats no longer the case with v4. Now you can optionally use elements in your dropdowns instead of just Action Another action
Menu dividers
Separate groups of related menu items with a divider. Action Another action Something else here Separated link
Action Another action Something else here
Separated link
Menu forms
Put a form within a dropdown menu, or make it into a dropdown menu, and use margin or padding utilities to give it the negative space you require. Email address Password Remember me Sign in New around here? Sign up Forgot password?
Email address
Password
Remember me
Sign in
New around here? Sign up Forgot password?
Email address Password Remember me Sign in Email address
Password
Remember me
Sign inActive menu items
Add .active to items in the dropdown to style them as active. Regular link Active link Another link
Regular link Active link Another link
Disabled menu items
Add .disabled to items in the dropdown to style them as disabled. Regular link Disabled link Another link
Regular link Disabled link Another link
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 its a good idea to always use it.
On touch-enabled devices, opening a dropdown adds empty [$.noop] mouseover handlers to the immediate children of the 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.
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 requiredRegardless 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 dropdowns 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.
Note when boundary is set to any value other than 'scrollParent', the style position: static is 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 elements dropdown. $[].dropdown['dispose'] Destroys an elements dropdown.
Events
All dropdown events are fired at the .dropdown-menus parent element and have a relatedTarget property, whose value is the toggling anchor element. 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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