Summary: CSS Containment gives web developers several ways of indicating that a subtree isn't influenced by the rest of the page. This may allow UAs to perform certain optimizations that they otherwise wouldn't be able to do.
Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1150081 Link to standard: https://drafts.csswg.org/css-contain/ Platform coverage: All platforms Estimated or target release: Firefox 68 Preference behind which this will be implemented: layout.css.contain.enabled (probably enabled by default in Nightly as of tomorrow, March 19) Is this feature enabled by default in sandboxed iframes? If not, is there a proposed sandbox flag to enable it? If allowed, does it preserve the current invariants in terms of what sandboxed iframes can do? Enabled by default everyhwere. It has no impact on what sandboxed iframes can do -- it's purely a way of constraining sizing/painting behavior. DevTools bug: None at the moment. This feature has subtle effects and I don't know of any useful devtools work to be done for it. Do other browser engines implement this? Chrome (Blink) implements it as of version 52. Their intent-to-implement: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/9W80Kw-z3ss web-platform-tests: https://wpt.fyi/results/css/css-contain https://wpt.fyi/results/css/vendor-imports/mozilla/mozilla-central-reftests/contain Is this feature restricted to secure contexts? No, not currently. Note that Chrome doesn't restrict it, so it could conceivably create interop issues if we restricted it without getting them to also commit to restricting it. On Mon, Mar 18, 2019 at 12:39 PM Daniel Holbert <dholb...@mozilla.com> wrote: > Yeah, sorry - our earlier intent-to-implement thread predated our current > boilerplate (which includes stuff like test coverage). And for > intent-to-ship, our boilerplate text is pretty minimal. > > Answering your direct question: yes, there is good web platform test > coverage for this feature. I'll post a followup with answers to our other > typical intent-to-implement fields, too. > > On Mon, Mar 18, 2019 at 12:07 PM James Graham <ja...@hoppipolla.co.uk> > wrote: > >> On 18/03/2019 19:01, Daniel Holbert wrote: >> > As of today (March 18th 2019), I intend to turn CSS Containment >> > <https://drafts.csswg.org/css-contain/> on by default on all >> platforms, in >> > Firefox Nightly 68. It has been developed behind the >> > 'layout.css.contain.enabled' preference. >> >> Apologies if I've missed it, but I can't see any mention of whether this >> feature has — meaningful — cross browser (i.e. wpt) tests in the ItI >> thread or here. >> _______________________________________________ >> dev-platform mailing list >> dev-platform@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-platform >> > _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
