whatwg / html

Closes #4417.

Closes #5565.

Fixes #5236.

Co-authored-by: Dominic Farolino <domfarolino@gmail.com>

Also adjust formatting and correct markup in the Web storage section.

Fixes #5067.

Tests: web-platform-tests/wpt#23585.

And also remove the remaining prefixed properties.

It's UTF-8 percent-encode (for code points) and percent-decode (for strings) now. See whatwg/url#503.

* Add a solid line to the top of the focusability examples table, to
  match the one at the end, and make it clearer to see that the example
  panels are part of the table.
* Add "and be sequentially focusable" before the list of elements that
  it is suggested browsers include in the "tab" order by default (when
  their tabindex value is null).

Closes #5087.

Tests: web-platform-tests/wpt#23500.

Less ambitious, but still solves a couple problems and makes room for future cleanup:

* Closes #3828 and closes #3830 by defining scheme validation fully.
* Also defines validation for unregisterProtocolHandler(), which was poorly defined but in its single implementation matches that of registerProtocolHandler().
* Removes the note about inline usage and gopher as it's unclear how valid that was to begin with and we're slowly moving towards only opening these top-level anyway.

Ideally a future cleanup defines an internal model for storing handlers and where that is (and is not) consulted. See #3043.

Tests: web-platform-tests/wpt#23458 (combined with the tests already there).

Closes #5500.

This also makes the special case more explicit by referring to the name
and eventTarget variables.

Tests: web-platform-tests/wpt#17573.

Fixes #4718.

Also tidy up some formatting.

Tests: web-platform-tests/wpt#23380.

Closes #4626.

Fixes #5503.

Closes #5244.

Tests: web-platform-tests/wpt#23309

* Removes "MQ" ("Media Queries"?) from the foundational layer.
* Fixes the typography for "Web IDL".
* Replaces "NPAPI" with "Service Workers" in the top layer.
* Replaces "JPEG GIF PNG" with "AV1 Opus PNG" to be a little less
  image-focused.
* Replaces "Encodings" with "Encoding" since that's the name of the
  spec in question.
* Replaces "Geo" with "IDB" (IndexedDB).
* Uses CSS to center things instead of doing so manually.

Closes #4711.

Fixes #5469.

Closes #5063. Follow-up: #5492.

This regressed in 916a923.

Fixes #5414.

What elements are considered interactive content is observable through
label element retargeting behavior, and all major rendering engines do
not consider tabindex for this purpose. In fact, considering tabindex
would be a Web-incompatible change according to
https://crbug.com/1065048.

This does not change document conformance requirements, since the cases
that would be affected now explicitly disallow elements with the
tabindex attribute, in addition to disallowing interactive content.

This causes scripts that move between documents between the preparation
and execution phases to not execute, aligning with most browsers. Closes
#2469.

This does not address #2137, which is about scripts moving between
documents between the parsing and preparation, or parsing and execution
phases.

Tests: web-platform-tests/wpt#19632

Follows heycam/webidl#870. Additionally, this
cross-links all of these extended attributes from their usage sites,
since I was updating them anyway.

Fixes #5467. This is only a problem for the dev edition, not the
multipage edition, because we have a redirect set up for
/multipage/images/* to /images/*.

I.e., not UA-defined, not user-agent-defined, and not user-agent defined.

Also link it up to Infra's fresh definition.

Tests: web-platform-tests/wpt#22678.

Closes #5445, and aligns with implementations.

See w3c/longtasks#80.