whatwg/html

Fixes part of #3487; what remains is to add it to ShadowRoot.

Closes #4888. f4e2907 refactored these
steps to remove the task as part of step 2, so step 7 is no longer
needed.

Closes #4879.

Previously, the spec vaguely noted that all agents and agent clusters
must be allocated at the appropriate time.

With this change, similar-origin window agents are allocated
imperatively during document and browsing context creation, along with
their corresponding agent clusters. The agent clusters are stored in the
appropriate browsing context group, via a map keyed by scheme and
registrable domain.

Fixes #4361. Further work on imperative agent/agent cluster allocation,
specifically for workers and worklets, is tracked in #4339.

* Run focusing steps after an animation frame
* Don't autofocus if the top-level document has focused area
* Don't autofocus if one of ancestor document has a :target element

Fixes #3551.  Fixes #4645.

* Add 'autofocus' to the global attribute list
* Move 'autofocus' IDL attribute from HTMLButtonElement, HTMLInputElement,
  HTMLSelectElement, HTMLTextAreaElement to HTMLOrSVGElement

Fixes #4563.

For semantics of something being empty (table cells in this case) we should only consider ASCII whitespace, as we do elsewhere.

Fixes #4854.

This behavior for text-transform has been implemented by many user agents and supported by
web developers via various "CSS normalizing" libraries.

Also align with WebKit and Blink on resetting other properties in the UA stylesheet, and align with WebKit/Blink/Gecko with having text-align: center on buttons.

Fixes #1310, fixes #4676.

Tests: web-platform-tests/wpt#17152

Closes #4863.

Closes #4815.

Part of #1583.

* Use the new tc39.es URLs instead of tc39.github.io.
* Reference ECMA-262 for dynamic import, instead of the separate
  import() proposal.
* Move the requirement about implementing ECMAScript
  Internationalization API down to be a sibling of other related repos.

This matches all implementations. Fixes #4855.

This is another tweak on top of 15cf23a
and 7ce0b47.

Fixes #3014

It seems this feature got added without an agreed upon plan. Firefox fires the loadstart event, but I cannot find evidence of the other events or them using the correct class.

Tests: web-platform-tests/wpt#18499.

Closes #1915. Closes #3860.

This aligns the HTML Standard with Chrome and Firefox rather than Safari.

Tests: web-platform-tests/wpt#18536.

Fixes #4762.

Fixes #4358. See also #2382.

Further code inspection and test-writing revealed that SVG <a> elements
get a 0 default tabIndex in all engines, and <object> elements get a 0
default tabIndex in Blink and WebKit. These were omitted in
15cf23a.

Previously, sandboxed navigation did not prevent navigation via the history API;
the check for the navigation was after the unload steps of the history
traversal. This adds an explicit check in those methods to prevent such
navigation.

Fixes #880.

Fixes #4798.

See heycam/webidl#750.

ab73443 introduced new custom element
callbacks, but continued to referring to there being four callbacks.
Let's stop stating how many callbacks there are.

Fixes #4822.

Fixes heycam/webidl#518.

Instead of delegating to the feature policy spec to initialize feature
policy after the document is created, initialize feature policy first
and pass it in while constructing the document.

This uses w3c/webappsec-feature-policy#324.

Introduced in 7c5555a by accident.

This ID was accidentally removed in 061e782. Thanks triple-underscore!

* Create the document after the global is created.
* Calculate the sandbox flags and origin before the document is created.
  This replaces the previously-declarative determination of the document
  origin.
* Thread through much of the previously-implicit state as explicit
  arguments.

This updates the tabIndex getter's default value to be 0 for a specific
list of element types, instead of the spec's previous "elements that are
focusable". This matches reality better; apart from minor edge cases
all three browser engines match this spec in observable behavior.

Closes #1786. Closes #4464. See the focus meta-bug in #4607 for related
discussions, including on adding an API that actually reflects whether
an element is focusable (like the tabIndex getter was kind-of supposed
to do).

Tests: web-platform-tests/wpt#17657

Fixes #2467.

A series of changes starting with 6440cca which removed the override
URL concept as well as intermediate cleanups such as e13762f eroded
the correctness of javascript: document URLs. Now it seems to be the
case that fixing this typo restores the correct handling for such URLs.

Addresses some concerns raised in #3989.

In particular:

* Disallow a leading +. Fixes #4720.
* Allow a trailing dot (in particular before %). Fixes #4736.

Tests: will be added and upstreamed in https://bugzilla.mozilla.org/show_bug.cgi?id=1562690.

Define serialization and deserialization steps for all built-in
NativeError types from the JavaScript specification. This change doesn't
cover DOMExceptions, which are covered by
heycam/webidl#732.

Fixes #4268.

Tests:
* web-platform-tests/wpt#17095
* web-platform-tests/wpt#17159

See tc39/ecma262#1312.

Fixes #4618.