api.Document.selectionchange_event - Safari incompatibility

What type of issue is this?

Browser bug (a bug with a feature that may impact site compatibility)

What information was incorrect, unhelpful, or incomplete?

Calling setBaseAndExtent() doesn't fire a selection-change event in Safari

What browsers does this problem apply to, if applicable?

Safari

What did you expect to see?

Expected document.onselectionchange() to be called. It is called in Chrome, Edge, Firefox after setBaseAndExtent() is called.

Did you test this? If so, how?

Commit 334f4bdf of https://github.com/MurrayIII/UnicodeMathML has the if statement that fixes the problem in Safari. Basically when navigating a math expression in the output window using right arrows (run the playground demo), some speech was missing in Safari. Calling document.onselectionchange() explicitly after calling setBaseAndExtent() fixes the problem in Safari.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Document/selectionchange_event

MDN metadata

Start with the api.Document.selectionchange_event entry and compare its Safari compatibility data with the reported behavior. Reproduce the setBaseAndExtent() case using the linked UnicodeMathML playground or commit 334f4bdf, then update the entry so it reflects the verified Safari behavior.