How Browsers Resolve Conflicting ARIA Roles and Properties in the Accessibility Tree

ARIA roles tell assistive technologies what an element is, but conflicts arise when multiple roles or mismatched ARIA properties appear on the same element. Browsers resolve these conflicts through a priority system: an explicit role attribute takes precedence, followed by implicit roles inferred from HTML tags, with certain roles like alert overriding more generic ones. ARIA properties such as aria-haspopup or aria-expanded can also alter how screen readers announce an element, and misaligning them with the assigned role can produce unpredictable results. To handle this, browsers build an accessibility tree from the DOM, CSS, and ARIA attributes, validating properties against roles and discarding conflicts. Understanding this resolution system is essential for developers debugging accessibility issues in complex or custom UI widgets.