This proposed feature would allow authors to annotate when an element and its descendants will not (or should not) affect the rest of the page. The primary intended benefit of such annotations is to allow browsers various layout and rendering optimizations.
As currently described <http://dev.w3.org/csswg/css-containment/>, this feature adds a css property 'contain' with four potential values 'layout', 'style', and 'paint' as well as 'strict', which is equivalent to the previous three. Details are still being worked out, as can be seen from the mailing list. <https://lists.w3.org/Archives/Public/www-style/2015Jun/0114.html> This feature is tracked by Bug 1150081. <https://bugzilla.mozilla.org/show_bug.cgi?id=1150081> Most likely, this will be implemented in FF42, gated behind "layout.css.contain.enabled". The timeline for performing the possible optimizations will probably be a fair bit longer. As far as I can tell, no other browsers are actively working on this, although patches for 'contain: strict' were posted to blink-dev <https://groups.google.com/a/chromium.org/d/msg/blink-dev/zAMZjAbxVJE/rDPK1jjwQigJ> . _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
