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

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.

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

Drop-down menu buttons are used when you want to offer several actions in a limited area.

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 <button> elements to better fit your potential needs.

Single button dropdowns

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:

<div class="btn-group dropdown">
  <button class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenuButton1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-controls="mycontrol1">
    <span>Dropdown button</span>
    <i class="icons-arrow-down"></i>
  </button>
  <div class="dropdown-menu dropdown-menu-right" aria-labelledby="dropdownMenuButton1" id="mycontrol1">
    <ul>
      <li class="dropdown-item"><a href="#">Action</a></li>
      <li class="dropdown-item"><a href="#">Another action</a></li>
      <li class="dropdown-item"><a href="#">Something else here</a></li>
    </ul>
  </div>
</div>

We recommend usage of dropdown-menu-right only, although by default dropdown’s menus are left aligned (CSS code conserved for compatibility reasons), to follow SNCF’s design guidelines.

Where are the colored variants of this component ?

In the SNCF’s “design guidelines”, most of the components are designed so that the designers and developers have no doubts for their usage. That’s why, even if other variants still exists inside CSS code, we display only those who are conform with Design System & Charte évolutive spirit. Don’t hesitate to contact us for more details and explications.

Disabled state

<div class="btn-group dropdown">
  <button class="btn btn-primary dropdown-toggle disabled" type="button" id="dropdownMenuButton2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-controls="mycontrol2">
    <span>Dropdown button</span>
    <i class="icons-arrow-down"></i>
  </button>
  <div class="dropdown-menu dropdown-menu-right" aria-labelledby="dropdownMenuButton2" id="mycontrol2">
    <ul>
      <li class="dropdown-item"><a href="#">Action</a></li>
      <li class="dropdown-item"><a href="#">Another action</a></li>
      <li class="dropdown-item"><a href="#">Something else here</a></li>
    </ul>
  </div>
</div>

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.

<div class="btn-group dropdown">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-controls="mycontrol3">
    <span>Dropdown</span>
    <i class="icons-arrow-down"></i>
  </button>
  <div class="dropdown-menu dropdown-menu-right" aria-labelledby="dropdownMenu2" id="mycontrol3">
    <ul>
      <li class="dropdown-item"><a href="#">Action</a></li>
      <li class="dropdown-item"><a href="#">Another action</a></li>
      <li class="dropdown-item"><a href="#">Something else here</a></li>
    </ul>
  </div>
</div>

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

<div class="dropdown-menu">
  <h6 class="dropdown-header">Dropdown header</h6>
  <ul>
    <li class="dropdown-item"><a href="#">Action</a></li>
    <li class="dropdown-item"><a href="#">Another action</a></li>
  </ul>
</div>

Separate groups of related menu items with a divider.

<div class="dropdown-menu">
  <ul>
    <li class="dropdown-item"><a href="#">Action</a></li>
    <li class="dropdown-item"><a href="#">Another action</a></li>
    <li class="dropdown-item"><a href="#">Something else here</a></li>
  </ul>
  <div class="dropdown-divider"></div>
  <ul>
    <li class="dropdown-item"><a href="#">Separated link</a></li>
  </ul>
</div>

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.

<div class="dropdown-menu">
  <form class="px-4 py-3">
    <div class="form-group">
      <label for="exampleDropdownFormEmail1">Email address</label>
      <input type="email" class="form-control" id="exampleDropdownFormEmail1" placeholder="email@example.com" title="email@example.com">
    </div>
    <div class="form-group">
      <label for="exampleDropdownFormPassword1">Password</label>
      <input type="password" class="form-control" id="exampleDropdownFormPassword1" placeholder="Password">
    </div>
    <div class="custom-control custom-checkbox mb-4">
      <input type="checkbox" name="exampleCheckbox1" class="custom-control-input" id="exampleCheckbox1" >
      <label class="custom-control-label" for="exampleCheckbox1">Remember me</label>
    </div>
    <button type="submit" class="btn btn-block btn-primary">Sign in</button>
  </form>
  <a class="btn btn-link dropdown-item d-inline-flex align-items-center text-primary" href="#">Forgotten password ?<i class="ml-1 icons-arrow-next icons-size-x5" aria-hidden="true"></i></a>
</div>

Active menu items

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

<div class="dropdown-menu">
  <ul>
    <li class="dropdown-item"><a href="#">Action</a></li>
    <li class="dropdown-item active"><a href="#" title="Active link actif">Active action</a></li>
    <li class="dropdown-item"><a href="#">Something else here</a></li>
  </ul>
</div>

Disabled menu items

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

<div class="dropdown-menu">
  <ul>
    <li class="dropdown-item"><a href="#">Action</a></li>
    <li class="dropdown-item disabled">Disabled action</li>
    <li class="dropdown-item"><a href="#">Something else here</a></li>
  </ul>
</div>

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.

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.

Via data attributes

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

<div class="dropdown">
  <button id="dLabel" type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-controls="dropdownDataAttributes">
    Dropdown trigger
  </button>
  <div class="dropdown-menu" aria-labelledby="dLabel" id="dropdownDataAttributes">
    ...
  </div>
</div>

Via JavaScript

Call the dropdowns via JavaScript:

$('.dropdown-toggle').dropdown()
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.

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 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.

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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