States/Properties: Invalid ARIA attribute value

Rule

ARIA attributes must conform to valid values

Background

ARIA attributes (i.e. starting with aria-, role) must contain valid values. These values must be spelled correctly and correspond to values that are allowed by the ARIA specification for a particular attribute to perform the intended accessibility function.

Many ARIA attributes accept a specific set of values. Allowed values, acceptable "undefined" values, and acceptable "default" values are required. Failure to comply with allowed values results in content that is not accessible to assistive technology users.

How to Fix

Fix the issue by ensuring the value inside each attribute is spelled correctly and corresponds to a valid value.

For example, aria-hidden="true" would pass, but aria-hidden="rtue" would fail, as would aria-hidden="pizza".