Fire "visibilitychange" events explicitly

[noamr]

Fire the event when unloading or traversing history,
instead of relying on hooks in other specs.

See w3c/page-visibility#51
and w3c/page-visibility#73

• At least two implementers are interested (and none opposed):

  • This is not a behavior change.

• Tests are written and can be reviewed and commented upon at:

  • wpt/page-visibility covers this.

• Implementation bugs are filed:

  • N/A
    (See WHATWG Working Mode: Changes for more details.)

---

/browsing-the-web.html ( diff )
/dom.html ( diff )
/indices.html ( diff )
/webappapis.html ( diff )

[marcoscaceres]

Make sure "pagevisibility" is also defined in https://html.spec.whatwg.org/multipage/indices.html#events-2

[noamr]

@domenic r?

[foolip]

Are there any tests for this? git grep pagevisibility shows not a single match in web-platform-tests for me.

[foolip]

Oh, the event name is "visibilitychange", I'll update the PR description.

[domenic]

This is wonderful.

[domenic]

Are there tests with regard to the relative order between visibilitychange and pagehide/pageshow?

[domenic]

Some other possible test gaps (but maybe I just can't find the tests):

• Test that cancelable is false
• Tests for the non-unload case, e.g. restoration from bfcache

I don't think we necessarily need to block on total coverage, given that this is a refactoring, but it might be good to avoid busywork if we need to go back and correct things later.

[domenic]

Oh, found a potentially big missing piece: the definition of onvisibilitychange.

It looks like this is a special Document-only event handler, like onreadystatechange. So I'd search for the two places onreadystatechange shows up and add it to those.

[noamr]

Oh, found a potentially big missing piece: the definition of onvisibilitychange.

It looks like this is a special Document-only event handler, like onreadystatechange. So I'd search for the two places onreadystatechange shows up and add it to those.

It exists in the pagevisibility spec, but I can move it here instead (which would make the pagevisibility spec somewhat empty)

[noamr]

Oh, found a potentially big missing piece: the definition of onvisibilitychange.
It looks like this is a special Document-only event handler, like onreadystatechange. So I'd search for the two places onreadystatechange shows up and add it to those.

It exists in the pagevisibility spec, but I can move it here instead (which would make the pagevisibility spec somewhat empty)

Done in new PR version.

[domenic]

You also need to add it to Document's IDL block

[noamr]

You also need to add it to Document's IDL block

Done

[domenic]

I was going to fix the spacing issue myself and merge, but then I saw the reference issue.

[domenic]

This is two-space indents, but it should be 1-space.

[noamr]

Fixed

[domenic]

This will just produce the literal text [[PAGEVIS]] in the output. In HTML you need to use <ref spec=PAGEVIS>. (And, if you do that, you need to not delete the reference on line 126072.)

[noamr]

Fixed

[domenic]

Great, thanks so much; this is way cleaner.