Accordion
Design annotations are needed for specific instances shown below, but for the standard accordion component, Carbon already incorporates accessibility.
What Carbon provides
No annotations for keyboard interaction or labels are needed. Carbon bakes in the interaction to support users.
Keyboard interactions
Each accordion is a tab stop. Space or Enter keys expand or collapse accordions, which are collapsed by default. Interactive elements within expanded accordions integrate into the tab order automatically.
Accordions are reached by Tab and activated by Space and Enter keys.
Labelling and states
The collapsed or expanded state of the accordions is programmatically set by default, eliminating the need for any text equivalent for the chevron icons.
Carbon handles the accessibility of the chevron indicators.
Design annotations
Design annotations are needed for the following instances.
Headings
Carbon accordions are not set as headings by default. For improved accessibility, annotate accordions as headings on the first occurrence in a product. Annotate the heading level of accordions as needed. See Indicate heading levels.
If accordion titles act as headings, annotate for development.
Alignment
Carbon chevrons are right-aligned by default, but left-aligned chevrons are more accessible for users with low vision, as the expanded/collapsed indicator is closer to the accordion title.
Annotate if the accordion chevrons should be left-aligned.
Developer considerations
Keep these considerations in mind if you’re modifying Carbon or creating a custom component:
- The accordion header has a role of
<button>, with anaria-expandedattribute set to"true"or"false". - The button has an
aria-controlsproperty set to the unique id of the panel it controls. - Since accordions are typically grouped together, Carbon puts each button inside a list item in an unordered list, which provides additional context to screen reader users; where only one accordion is used, it should not be put in a list.
- When accordion titles are used as headings, the buttons are also wrapped in an element with an appropriate heading level; ARIA can be used to set both the heading role and the level (via
aria-level). - See the ARIA authoring practices for more guidance.