Collapsible

Collapsed

Expanded

A collapsible is a component to mark expandable and collapsible regions. It has states, roles, attributes and behaviour in accordance with guidelines given in Using the WAI-ARIA aria-expanded state to mark expandable and collapsible regions, ARIA Authoring Practices, Button, and Building Accessible Buttons with ARIA: A11y

Collapse All the Things

The collapsible acts as a "pluggable" component. It uses a <button> element or an element with role="button" to control one or more collapsible regions. You can make virtually any HTML element collapsible by adding two classes, mdlext-js-collapsible to the element that should control the collapsible region(s), and one of the classes mdlext-collapsible-group or mdlext-collapsible-region to the element that should collapse/expand. The collapsible component uses the aria-controls property to hold a list of one or more collapsible regions. The aria-expanded state indicates whether region(s) controlled by the component is currently expanded or collapsed.

To include a MDLEXT collapsible component:

 1. Code a <button> element; this is the clickable toggle that will show and hide the collapsible region(s). Inside the button, code a <span> element to hold the button caption text.

<button>
  <span>Click to toggle</span>
</button>

 2. Add the mdlext-js-collapsible class to define the element as a collapsible component.

<button class="mdlext-js-collapsible">
  <span>Click to toggle</span>
</button>

 3. Optionally add the mdlext-collapsible class, which will add a pointer cursor to the collapsible component.

<button class="mdlext-js-collapsible mdlext-collapsible">
  <span>Click to toggle</span>
</button>

 4. Optionally add a state icon. Code a <i> element with class mdlext-aria-expanded-more-less. The state icon should indicate whether the collapsible region is expanded or not.

<button class="mdlext-js-collapsible">
  <span>Click to toggle</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</button>

 5. Code a <div> element with class mdlext-collapsible-group or mdlext-collapsible-region to define the element as a collapsible region.

<div class="mdlext-collapsible-group">
</div>

 6. Add content inside the collapsible container.

<div class="mdlext-collapsible-group">
  <p>Content goes here ...</p>
</div>

After page load, the component will add all required Aria states, roles and attributes not already present in markup.

<button class="mdlext-js-collapsible is-upgraded" 
  data-upgraded=",MaterialExtCollapsible" 
  aria-expanded="false" aria-controls="group-4ek31z6jeeag">
  <span>Click to toggle</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</button>
<div class="mdlext-collapsible-group" id="group-4ek31z6jeeag" role="group" hidden>
  <p>Content goes here ...</p>
</div>

Instead of letting the collapsible component add all the WAI-ARIA stuff, add it yourself in markup. The component will not override attributes already present in markup.

<div class="mdlext-js-collapsible" role="button" 
  aria-expanded="false" aria-controls="group-1">
  <span>Click to toggle</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</div>
<div class="mdlext-collapsible-group" id="group-1" role="group" hidden>
  <p>Content Region #1 goes here ...</p>
</div>

role="group" vs role="region"

The group role is used to identify a set of user interface objects which, in contrast with a region, are not intended to be included in a table of contents or a page summary (such as the structures that are dynamically created by a script or assistive technologies); a group should not be considered a major perceivable section on a page. When the role is added to an element, the browser will send out an accessible group event to assistive technology products which can then notify the user about it.

To define an element as collapsible add one of the classes
mdlext-collapsible-group or mdlext-collapsible-region. The component will set the role attribute to group or region accordingly.

Group: A set of user interface objects which are not intended to be included in a page summary or table of contents by assistive technologies.

Region: A large perceivable section of a web page or document, that is important enough to be included in a page summary or table of contents, for example, an area of the page containing live sporting event statistics.

Use a <div> element as a collapsible component.

It's easier to style a div compared to a button. For example, you can not style a button as a flexible box!

<div class="mdlext-js-collapsible mdlext-collapsible" aria-expanded="true">
  <span>Click to toggle</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</div>
<div class="mdlext-collapsible-region">
  <p>Content goes here ...</p>
</div>

For further control with styling, it is possible to wrap the button element inside the collapsible component. The wrapped element becomes the clickable/focusable area and must have class mdlext-collapsible applied.

<header class="mdlext-js-collapsible" aria-expanded="true">
  <div class="mdlext-collapsible"> 
    <span>Click to toggle</span>
    <i class="mdlext-aria-expanded-more-less"></i>
  </div>  
</header>
<div class="mdlext-collapsible-region">
  <p>Content goes here ...</p>
</div>

one-to-many

You can create a one-to-many relationship by supplying a space separated list of ids, representing different, simultaneously controlled elements.

<div class="medext-js-collapsible">
  <div class="mdlext-collapsible" role="button" 
    aria-controls="collapsible-1 collapsible-3">A topic</div>
</div>

<div id="collapsible-1" class="mdlext-collapsible-group">
  <p>Topic 1 is all about being Topic 1 and may or 
  may not have anything to do with other topics.</p>
</div>

<div id="collapsible-2" class="mdlext-collapsible-group">
  <p>Topic 2 is all about being Topic 2 and may or 
  may not have anything to do with other topics.</p>
</div>

<div id="collapsible-3" class="mdlext-collapsible-group">
  <p>Topic 3 is all about being Topic 3 and may or 
  may not have anything to do with other topics.</p>
</div>

If the aria-controls attribute is provided in markup, the component will not attempt to determine corresponding collapsible regions. In the markup above, only collapsible-1 and collapsible-3 will be controlled by the component.

Remove the aria-controls attribute if you want the component to determine the collapsible regions to be included.

Examples

Collapsibles, with many collapsible regions.

<!-- first collapsible -->
<button class="mdlext-js-collapsible mdlext-collapsible">
  <span>Click to toggle collapsible #1</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</button>
<div class="mdlext-collapsible-region">
  <p>#1.1</p>
</div>
<div class="mdlext-collapsible-region">
  <p>#1.2</p>
</div>

<!-- second collapsible -->
<header class="mdlext-js-collapsible mdlext-collapsible">
  <span>Click to toggle collapsible #2</span>
  <i class="mdlext-aria-expanded-more-less"></i>
</header>
<div class="mdlext-collapsible-region">
  <p>#2.1</p>
</div>

<p>This paragraph will not collapse</p>

<div class="mdlext-collapsible-region">
  <p>#2.2</p>
</div>
<div class="mdlext-collapsible-region">
  <p>#2.3</p>
</div>

Nested collapsibles.

<style>
  .mdlext-collapsible-region .mdlext-js-collapsible,
  .mdlext-collapsible-region .mdlext-collapsible-region {
    margin-left: 16px;
  }
</style>

<button class="mdlext-js-collapsible mdl-button mdl-button--colored mdl-button--raised">
  Click to toggle
</button>
<div class="mdlext-collapsible-region">
  <p>A collapsible region</p>

  <button class="mdlext-js-collapsible mdl-button mdl-button--accent mdl-button--raised">
    Click to toggle nested #1
  </button>
  <div class="mdlext-collapsible-region">
    <p>A nested collapsible region</p>

    <button class="mdlext-js-collapsible mdl-button mdl-button--raised 
      mdl-button--colored mdl-color--deep-orange-100">
      Click to toggle nested #2
    </button>
    <div class="mdlext-collapsible-region">
      <p>Last region</p>
    </div>
  </div>
</div>

Collapsible MDL Card.

<!-- The card need some styling to act as a collapsible -->
<style>
  .mdl-card.welcome-card {
    min-height: 0;
    max-width: 640px;
    width: auto;
  }
  .mdl-card.welcome-card > .mdl-card__title {
    -webkit-box-pack: start;
    -webkit-justify-content: flex-start;
    -ms-flex-pack: start;
    justify-content: flex-start;
    height: 176px;
    min-height: 64px;
    padding-top: 0;
    padding-bottom: 0;
    color: #fff;
    background: url('./assets/welcome_card.jpg') top / cover;
  }
  .mdl-card.welcome-card .mdl-card__title:focus {
    /* Must focus ring must be inside title since mdl-card has overflow:hidden */
    outline-offset: -4px;
  }
  .mdl-card.welcome-card .mdl-card__title > * {
    -webkit-align-self: center;
    -ms-flex-item-align: center;
    align-self: center;
  }
  .mdl-card.welcome-card .mdl-card__supporting-text {
    width: auto;
  }
  .mdl-card.welcome-card .mdl-card__actions {
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
  }
  .welcome-card > .mdl-card__title .mdl-card__title-text {
    -webkit-align-self: flex-end;
    -ms-flex-item-align: end;
    align-self: flex-end;
    padding-bottom: 16px;
  }
  .welcome-card > .mdl-card__title[aria-expanded='false'] {
    height: 64px;
  }
  .welcome-card > .mdl-card__title[aria-expanded='false'] .mdl-card__title-text {
    -webkit-align-self: center;
    -ms-flex-item-align: center;
    align-self: center;
    padding-bottom: 0;
  }
  .welcome-card > .mdl-card__menu {
    color: #ffffff;
  }
</style>

<div class="welcome-card mdl-card mdl-shadow--2dp">
  <header class="mdl-card__title mdlext-js-collapsible mdlext-collapsible">
    <h2 class="mdl-card__title-text">A Collapsible Card</h2>
  </header>
  <section class="mdl-card__supporting-text mdlext-collapsible-region">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit.
    Mauris sagittis pellentesque lacus eleifend lacinia...
  </section>
  <footer class="mdl-card__actions mdl-card--border mdlext-collapsible-region">
    <button class="mdl-button mdl-button--colored mdl-js-button mdl-js-ripple-effect">
      Get Started
    </button>
  </footer>
  <div class="mdl-card__menu">
    <button class="mdl-button mdl-button--icon mdl-js-button mdl-js-ripple-effect">
      <i class="material-icons">share</i>
    </button>
  </div>
</div>

Create your own state icon with SASS.

The _mixins.scss has a mixin which can be used to create custom state icons.

@charset "UTF-8";
.my-aria-expanded-state {
  @include mdlext-aria-expanded-toggle($icon: 'arrow_downward', $icon-expanded: 'arrow_upward');
}

More examples

• The snippets/collapsible.html and the tests provides more detailed examples.
• Try out the live demo

Characteristics

Keyboard interaction

• Space or Enter: toggle the corresponding collapsible region(s).

Mouse interaction

• Click: toggle the corresponding collapsible region(s).

Events

The collapsible component emits a custom toggle event when the component is clicked, Enter key or Space key is pressed or one of the methods expand. collapse or toggle is called. The event is emitted before the actual toggling occurs. Call event.preventDefault() to cancel toggling.

The detail object parameter has the following structure:

detail: {
  action // 'expand' or collapse'  
}

Set up an event listener to receive the toggle event.

var someCondition = false;
document.querySelector('#my-collapsible').addEventListener('toggle', function(e) {
  console.log('Toggle action:', e.detail.action);
  if(someCondition) {
    // Stop toggling
    e.preventDefault();
  }
  someCondition = !someCondition;
});

Public methods

getControlElement()

Get the element that controls the collapsible region(s).

getRegionElements()

Get region elements controlled by this collapsible.

addRegionElements(...elements)

Add collapsible region(s).

removeRegionElements(...elements)

Remove collapsible region(s).

expand()

Expand corresponding collapsible region(s).

collapse()

Collapse corresponding collapsible region(s).

toggle()

Toggle corresponding collapsible region(s).

const component = document.querySelector('#my-collapsible');
component.MaterialExtCollapsible.toggle();

isExpanded()

Check whether component has aria-expanded state set to true.

isDisabled()

Check whether component has aria-disabled state set to true.

enableToggle()

Enables toggling of collapsible region(s).

disableToggle()

Disables toggling of collapsible region(s).

Configuration options

The MDLEXT CSS classes apply various predefined visual and behavioral enhancements to the accordion.

Available classes and their effects.

Available WAI-ARIA roles, states, and properties

Other collapsible examples

• ARIA Examples, Progressive collapsibles
• Open Ajax, Example 20 - Hide/Show: Region follows button
• Open Ajax, Example 21 - Hide/Show: Region does not follow button
• Open Ajax, Example 22 - Hide/Show: Region is exclusive