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| layout | title | group |
|---|---|---|
| docs | Collapse | components |
The Bootstrap collapse plugin allows you to toggle content on your pages with a bit of JavaScript and some classes. Flexible plugin that utilizes a handful of classes (from the required [transitions plugin]({{ site.baseurl }}/components/transitions/)) for easy toggle behavior.
Contents
- Will be replaced with the ToC, excluding the "Contents" header {:toc}
Example
Click the buttons below to show and hide another element via class changes:
.collapsehides content.collapsingis applied during transitions.collapse.inshows 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.
{% example html %}
Accordion example
Extend the default collapse behavior to create an accordion.
{% example html %}
Accessibility
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:
.collapsehides the content.collapse.inshows the content.collapsingis 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:
{% highlight js %} $('.collapse').collapse() {% endhighlight %}
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 | false | If a selector 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 panel class) |
| toggle | boolean | true | Toggles the collapsible element on invocation |
Methods
.collapse(options)
Activates your content as a collapsible element. Accepts an optional options object.
{% highlight js %} $('#myCollapsible').collapse({ toggle: false }) {% endhighlight %}
.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.
| 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). |
{% highlight js %} $('#myCollapsible').on('hidden.bs.collapse', function () { // do something… }) {% endhighlight %}