Normative follow-on from#434

The spec was updated to note that the summary element doesnt' always map to the button element. The allowed attributes indicated that all attributes that were applicable to the button role were allowed. However, in practice this doesn't make sense and could break or be in contradiction to the implicit semantics.

The allowed aria-* attributes for the button role include

• aria-disabled
• aria-haspopup
• aria-expanded
• aria-pressed

Edit: after testing,aria-expanded andaria-pressed provide zero value on asummary element, as they are presently ignored by user agents (browsers/AT).https://codepen.io/scottohara/pen/ZEjZPoR

<details open><summary aria-pressed=false>test 1</summary>aria-pressed on summary element</details>
<details open>
<summary aria-expanded=false>test 2</summary>
aria-expanded=false on summary element
</details>
<details open>
<summary aria-haspopup=dialog>test 3</summary>
aria-haspopup=dialog on summary element
</details>
<details open>
<summary aria-disabled=true>test 4</summary>
aria-disabled=true on summary element
</details>

test 1JAWS/NVDA+Chromium/Gecko - attribute ignoredNarrator+Edge - attribute ignored / UIA ignores attriOS/macos safari/firefox+VO - ignoredtest 2JAWS/NVDA+Chromium/Gecko - attribute ignoredNarrator+Edge - attribute ignored / UIA ignores attriOS/macos safari/firefox+VO - ignoredtest 3JAWS/NVDA+Chromium/Gecko - announces as a button menuNarrator+Edge - has popupmacOS VO + Safari - has popupiOS VO + safari, macOS VO firefox - ignoredtest 4JAWS/NVDA+Chromium/Gecko - disabled state conveyedNarrator+Edge - disablediOS/macOS Safari/firefox+VO - disabled

Concerning the allowed roles for a summary element. A summary element can be one of two things, the 'summary for its parent details' - where it acts as the triggering element for the disclosure widget. Or, if it doesn't meet the conditions to be that (e.g., it is not a child of a details element, or it is not the first instance of a summary element - e.g., it's the 2+ summary element within a details), then it is treated as a generic element, so any role/attribute should be allowed.

test cases -https://w3c.github.io/html-aria/tests/summary-allowances.html

• HTML Validator
• IBM equal access accessibility checker
• axe-core
• ARC toolkit

(linked issues to each checker referenced in the following thread)

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