twbootstrap/site/content/docs/4.6/components/collapse.md

layout	title	description	group	toc
docs	Collapse	Toggle the visibility of content across your project with a few classes and our JavaScript plugins.	components	true

How it works

The collapse JavaScript plugin is used to show and hide content. Buttons or anchors are used as triggers that are mapped to specific elements you toggle. Collapsing an element will animate the height from its current value to 0. Given how CSS handles animations, you cannot use padding on a .collapse element. Instead, use the class as an independent wrapping element.

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Example

Click the buttons below to show and hide another element via class changes:

• .collapse hides content
• .collapsing is applied during transitions
• .collapse.show shows content

Generally, we recommend using a button with the data-target attribute. While not recommended from a semantic point of view, you can also use a link with the href attribute (and a role="button"). In both cases, the data-toggle="collapse" is required.

{{< example >}}

Link with href Button with data-target

Some placeholder content for the collapse component. This panel is hidden by default but revealed when the user activates the relevant trigger.

{{< /example >}}

Multiple targets

A <button> or <a> can show and hide multiple elements by referencing them with a JQuery selector in its href or data-target attribute. Multiple <button> or <a> can show and hide an element if they each reference it with their href or data-target attribute

{{< example >}}

Toggle first element Toggle second element Toggle both elements

Some placeholder content for the first collapse component of this multi-collapse example. This panel is hidden by default but revealed when the user activates the relevant trigger.

Some placeholder content for the second collapse component of this multi-collapse example. This panel is hidden by default but revealed when the user activates the relevant trigger.

{{< /example >}}

Accordion example

Using the [card]({{< docsref "/components/card" >}}) component, you can extend the default collapse behavior to create an accordion. To properly achieve the accordion style, be sure to use .accordion as a wrapper.

{{< example >}}

Collapsible Group Item #1

<div id="collapseOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordionExample">
  <div class="card-body">
    Some placeholder content for the first accordion panel. This panel is shown by default, thanks to the <code>.show</code> class.
  </div>
</div>

Collapsible Group Item #2

Some placeholder content for the second accordion panel. This panel is hidden by default.

Collapsible Group Item #3

And lastly, the placeholder content for the third and final accordion panel. This panel is hidden by default.

{{< /example >}}

Accessibility

Be sure to add aria-expanded to the control element. This attribute explicitly conveys the current state of the collapsible element tied to the control to screen readers and similar assistive technologies. If the collapsible element is closed by default, the attribute on the control element should have a value of aria-expanded="false". If you've set the collapsible element to be open by default using the show class, set aria-expanded="true" on the control instead. The plugin will automatically toggle this attribute on the control based on whether or not the collapsible element has been opened or closed (via JavaScript, or because the user triggered another control element also tied to the same collapsible element). If the control element's HTML element is not a button (e.g., an <a> or <div>), the attribute role="button" should be added to the element.

If your control element is targeting a single collapsible element – i.e. the data-target attribute is pointing to an id selector – you should add the aria-controls attribute to the control element, containing the id of the collapsible element. Modern screen readers and similar assistive technologies make use of this attribute to provide users with additional shortcuts to navigate directly to the collapsible element itself.

Note that Bootstrap's current implementation does not cover the various keyboard interactions described in the WAI-ARIA Authoring Practices 1.1 accordion pattern - you will need to include these yourself with custom JavaScript.

Usage

The collapse plugin utilizes a few classes to handle the heavy lifting:

• .collapse hides the content
• .collapse.show shows the content
• .collapsing is added when the transition starts, and removed when it finishes

These classes can be found in _transitions.scss.

Via data attributes

Just add data-toggle="collapse" and a data-target to the element to automatically assign control of one or more collapsible elements. The data-target attribute accepts a CSS selector to apply the collapse to. Be sure to add the class collapse to the collapsible element. If you'd like it to default open, add the additional class show.

To add accordion-like group management to a collapsible area, add the data attribute data-parent="#selector". Refer to the demo to see this in action.

Via JavaScript

Enable manually with:

$('.collapse').collapse()

Options

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

Name	Type	Default	Description
parent	selector | jQuery object | DOM element	false	If parent is provided, then all collapsible elements under the specified parent will be closed when this collapsible item is shown. (similar to traditional accordion behavior - this is dependent on the card class). The attribute has to be set on the target collapsible area.
toggle	boolean	true	Toggles the collapsible element on invocation

Methods

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.collapse(options)

Activates your content as a collapsible element. Accepts an optional options object.

$('#myCollapsible').collapse({
  toggle: false
})

.collapse('toggle')

Toggles a collapsible element to shown or hidden. Returns to the caller before the collapsible element has actually been shown or hidden (i.e. before the shown.bs.collapse or hidden.bs.collapse event occurs).

.collapse('show')

Shows a collapsible element. Returns to the caller before the collapsible element has actually been shown (i.e. before the shown.bs.collapse event occurs).

.collapse('hide')

Hides a collapsible element. Returns to the caller before the collapsible element has actually been hidden (i.e. before the hidden.bs.collapse event occurs).

.collapse('dispose')

Destroys an element's collapse.

Events

Bootstrap's collapse class exposes a few events for hooking into collapse functionality.

Event Type	Description
show.bs.collapse	This event fires immediately when the show instance method is called.
shown.bs.collapse	This event is fired when a collapse element has been made visible to the user (will wait for CSS transitions to complete).
hide.bs.collapse	This event is fired immediately when the hide method has been called.
hidden.bs.collapse	This event is fired when a collapse element has been hidden from the user (will wait for CSS transitions to complete).

$('#myCollapsible').on('hidden.bs.collapse', function () {
  // do something...
})