Ensure ARIA attributes are allowed for an element's role

ARIA roles and attributes help screen readers provide missing information about an element. For these roles and attributes to make sense, each ARIA role supports a specific subset of aria-* attributes (see ARIA roles definitions). Lighthouse reports any mismatches between roles and aria-* attributes:

Lighthouse audit showing ARIA attributes do not match their roles
Fig. 1 — ARIA attributes do not match their roles

Key Term: ARIA attributes let you modify the way HTML elements are represented to assitive technologies like screen readers. Learn more in this Introduction to ARIA.

How Lighthouse finds ARIA mismatches

Lighthouse uses the WAI ARIA specification - Definition of roles to check for mismatches between ARIA roles and attributes. Each role has a subset of "supported states and properties" and "inherited states and properties". Any element with that role can only use the attributes in the role's definition.

Lighthouse fails this audit when it finds an attribute that isn't allowed for a role on an elememnt. In the example Lighthouse audit above, the aria-checked attribute is not allowed on the role=list, so the audit fails. This makes sense—as list elements wouldn't have a state of checked, so applying a checked state would be confusing to screen reader users.

How this audit impacts overall Lighthouse score

Lighthouse flags this as a low severity issue. It is important to fix, and probably indicates a mistaken assumption in your code, but a disallowed attribute won't break the element's role. In the example above, the element is still announced as a list and the aria-checked attribute would be ignored.

How to avoid ARIA mismatches

To avoid ARIA mismatches, refer to the WAI ARIA Definition of roles. ARIA explicitly defines which attributes are allowed for any given role and for every attribute. Link to the role from the specification, and check the attributes allowed. So long as an attribute is listed for that role, you can use it.

For more information on this audit, see Elements must only use allowed ARIA attributes.

More information

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