A closed <details> reads its hidden content, and its summary without button/collapsed #254

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1. Elizabeth1979

   added a commit that references this issue on Oct 17, 2026

   Speak through Guidepup's virtual screen reader instead of our own rul…

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2. cmorten commented on Oct 17, 2026

   

   cmorten

   on Oct 17, 2026

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   R.E. "the summary read as a collapsed button"

   Some quote/refs from specs:

   [wai-aria-1.2] - No corresponding role
   Computed Role - If the element is the first child of its type within a parent details element: html-summary. Otherwise, if it is not the first child of its type of a parent details element, or it is not a child of a details element: generic role

   The specific accessibility APIs (UIA, AX, etc.) do typically expose as some form of expand/collapse like button.

   REF: https://www.w3.org/TR/html-aam-1.0/#el-summary

   No role if the summary element is a summary for its parent details element.

   Note
   The exposed role of a summary element can vary depending on the user agent and assistive technology.

   REF: https://www.w3.org/TR/html-aria/#docconformance

   From memory/experience the expected role of summary element is somewhat contested, but my read is that officially it doesn't have an implicit role in the sense that this library typically exposes, and that user agents and assistive technologies have (because to many this feels like a gap given it is an interactive button like thing) made up their own choices on how to expose it (prompting the note in the ARIA in HTML spec).

   Generally I've looked to be spec aligned and not implementation aligned (citation needed, probably not done this consistently!) which hints at us adopting the spec's No corresponding role definition for <summary> elements.

   If you have spec or WPT links that speak to the contrary then please share and can reconsider!

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   R.E. "HTML standard does not render a closed details' content beyond its summary" need to have a deeper look, nothing stands out that can see from the aria related specs, but if HTML specs consider it not rendered then agree we should treat it like it's either not there!
3. cmorten commented on Oct 17, 2026

   

   cmorten

   on Oct 17, 2026

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   2. The second child element is a slot that is expected to take the details element's remaining descendants, if any. This element has no contents.

   This element is expected to match the '::details-content' pseudo-element.

   This element is expected to have its style attribute set to "display: block; content-visibility: hidden;" when the details element does not have an open attribute. When it does have the open attribute, the style attribute is expected to be set to "display: block;".

   Because the slots are hidden inside a shadow tree, this style attribute is not directly visible to author code. Its impacts, however, are visible. Notably, the choice of content-visibility: hidden instead of, e.g., display: none, impacts the results of various APIs that query layout information.

   REF: https://html.spec.whatwg.org/multipage/rendering.html?utm_source=chatgpt.com#the-details-and-summary-elements

   So the HTML described behaviour of a closed details-summary is to apply content-visibility: hidden. This then points to:

   hidden

   The element skips its contents.

   The skipped contents must not be accessible to user-agent features, such as find-in-page, tab-order navigation, etc., nor be selectable or focusable.

   Note: This is similar to giving the contents display: none.

   REF: https://www.w3.org/TR/css-contain-2/?utm_source=chatgpt.com#content-visibility

   The "must not be accessible to user-agent features, such as find-in-page, tab-order navigation, etc., nor be selectable or focusable" and comparison to display: none settles it IMO, so I agree, we should omit the children of a collapsed <details> element from the constructed tree.
4. cmorten

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   bugSomething isn't workingSomething isn't working

   on Oct 17, 2026
5. cmorten

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6. cmorten

   added a commit that references this issue on Oct 22, 2026

   fix: omit the content of a closed details element from the tree (#266)

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7. cmorten commented on Oct 23, 2026

   

   cmorten

   on Oct 23, 2026

   Last edited by cmorten

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   With #266 merged I believe this is complete.

   Message if disagree (with citations!) r.e. the button role and we can discuss further!
8. cmorten

   closed this as completedon Oct 23, 2026