[DRAFT] Add the concept of an event source.

[alice]

This concept is used to propagate events into the source's tree under certain circumstances.

See whatwg/dom#1377 for the definition of the concept and how it is used.

Note: I'm not sure how best to go about this, but this is my best guess. ToggleEvent already has a source, so it might be enough for it to implicitly be the source used in algorithms, the way relatedTarget is. However, SubmitEvent has an analogous but differently named member, submitter, which I think should be used the same way.

• At least two implementers are interested (and none opposed):
  • …
  • …
• Tests are written and can be reviewed and commented upon at:
  • …
• Implementation bugs are filed:
  • Chromium: …
  • Gecko: …
  • WebKit: …
  • Deno (only for timers, structured clone, base64 utils, channel messaging, module resolution, web workers, and web storage): …
  • Node.js (only for timers, structured clone, base64 utils, channel messaging, and module resolution): …
• Corresponding HTML AAM & ARIA in HTML issues & PRs:
• MDN issue is filed: …
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

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/form-control-infrastructure.html ( diff )
/infrastructure.html ( diff )
/interaction.html ( diff )