Intent to Deprecate and Remove: webkitallowfullscreen content attribute

[Philip Jägenstedt]

Primary eng (and PM) emails

phi...@opera.com

Summary

Remove all knowledge of the webkitallowfullscreen content attribute, so that only the unprefixed allowfullscreen attribute determines whether to allow the iframe's contents to go fullscreen.

Spec: http://whatwg.org/html#attr-iframe-allowfullscreen and http://fullscreen.spec.whatwg.org/#fullscreen-enabled-flag

Motivation

The unprefixed allowfullscreen attribute is supported since February 2013:

http://trac.webkit.org/changeset/143533

The current logic is that if either of the two attributes is present, webkitRequestFullscreen() is allowed. This is exposed via Document.webkitFullscreenEnabled.

Having both attributes complicates two changes I want to make:

Element.requestFullscreen() and Document.fullscreenEnabled (part of unprefixing the Fullscreen API) should only consider allowfullscreen, and would require split code paths for the prefixed and unprefixed API.

HTMLIFrameElement.allowFullscreen should reflect the allowfullscreen content attribute. Implementing it without dropping webkitallowfullscreen would mean that the allowFullscreen IDL attribute may not match whether fullscreen is allowed, which seems silly.

Compatibility Risk

Content in iframes which have only the webkitallowfullscreen attribute will stop being able to go fullscreen.

Alternative implementation suggestion for web developers

Use the allowfullscreen attribute.

Usage information from UseCounter

http://www.chromestatus.com/metrics/feature/timeline/popularity/315

The counter is for when the attribute would actually make a difference, not merely its presence. It is in M35 which reached the stable channel on May 20. At that time, the counter went from 0 to oscillating between 0 and 0.0001%.

Entry on chromestatus.com, crbug.com, or MDN

None.

Requesting approval to remove too?

Yes, no deprecation period seems useful given the low usage.

[Eric Seidel]

Lgtm

[Adam Barth]

LGTM

[Darin Fisher]

LGTM