Add the interesttarget attribute

[foolip]

• 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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/browsers.html ( diff )
/form-elements.html ( diff )
/image-maps.html ( diff )
/index.html ( diff )
/indices.html ( diff )
/popover.html ( diff )
/semantics-other.html ( diff )
/text-level-semantics.html ( diff )
/interesttarget.html ( diff )

[foolip]

This is an initial translation of https://open-ui.org/components/interest-invokers.explainer/ to spec language, with a lot of things incomplete.

@mfreed7 I think the two biggest points of uncertainty I have now are the integration with mouse/keyboard/touch input on the one end, and with CSS on the other.

For showing interest, the timing of these algorithms relative to "mouseover" and other events needs to be defined.

For CSS, the fact that there are CSS properties controlling the timing means we need to think about:

• When do we look at the computed style to extract those times?
• Is there a state machine with timers, and is anything observable between the initial sign of interest and when we run "capture interest"?

There are many more minor TODOs, but I'd like to get the high-level flow settled first.