Collapse

Plugin dependency

Collapse requires the transitions plugin to be included in your version of Bootstrap.

Example

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

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

You can use a link with the href attribute, or a button with the data-target attribute. In both cases, the data-toggle="collapse" is required.

Accordion example

Extend the default collapse behavior to create an accordion with the panel component.

It's also possible to swap out .panel-bodys with .list-groups.

Make expand/collapse controls accessible

Be sure to add aria-expanded to the control element. This attribute explicitly defines the current state of the collapsible element to screen readers and similar assistive technologies. If the collapsible element is closed by default, it should have a value of aria-expanded="false". If you've set the collapsible element to be open by default using the in class, set aria-expanded="true" on the control instead. The plugin will automatically toggle this attribute based on whether or not the collapsible element has been opened or closed.

Additionally, if your control element is targetting a single collapsible element – i.e. the data-target attribute is pointing to an id selector – you may add an additional 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.

Usage

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

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

These classes can be found in component-animations.less.

Via data attributes

Just add data-toggle="collapse" and a data-target to the element to automatically assign control of a collapsible element. 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 in.

To add accordion-like group management to a collapsible control, 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="".

Methods

.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.

.collapse('show')

Shows a collapsible element.

.collapse('hide')

Hides a collapsible element.

Events

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

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