Cross-root ARIA

• WIP Spec draft

Public summary from WCCG

https://w3c.github.io/webcomponents-cg/#cross-root-aria

GitHub Issue(s):

• WICG/aom#169
• WICG/aom#107
• WICG/webcomponents#917
• WICG/webcomponents#916

Description

1. Shadow root encapsulation currently prevents references between elements in different roots. Cross-root ARIA references would re-enable this platform feature within shadow roots.
2. It's not possible to "forward" ARIA attributes from a custom element host into elements in the host's shadow root. For instance, a custom input that wants to allow users to customize the ARIA role, has no way to forward the role attribute to the encapsulated native input.

Motivation

Content on the web be accessible is critically important. Making web component content accessible currently requires many complicated and only partially-successful workarounds, such as:

• Observing and moving ARIA-related attributes across elements (for role, etc.)
• Using non-standard attributes for ARIA features, in order to apply them to elements in a shadow root.
• Requiring that custom elements users wrap/slot elements so that ARIA attributes can be placed directly on them. This gets very complicated as the number of slotted inputs and levels of shadow root nesting increase.
• Duplicating nodes across shadow root boundaries
• Abandoning Shadow DOM

Explainers

• Cross-root ARIA Delegation API