Re: Deferring CSS load for unmatched Media Queries

Yes, this is an accurate description.


On Tue, Feb 5, 2013 at 12:56 AM, Tab Atkins Jr. <jackalmage@gmail.com>wrote:

> So, it sounds like you want to delineate three distinct categories of
> stylesheets:
>
> 1. Essential stylesheets.  All current stylesheets are in this
> category by default.  Essential stylesheets load eagerly, block script
> execution during parsing, etc.
> 2. Low-priority stylesheets.  These are used on the page, but aren't
> important to load quickly.  (That is, a FOUC is okay, or maybe you
> won't add the elements that need the style until after you're sure the
> style has loaded.)  To handle potential race issues with page script,
> the OM for these stylesheets will be nulled until the author
> explicitly requests them, even if the sheet has already loaded.
> 3. High-prio but optional stylesheets.  These are necessary early in
> the page, but may not be used, due to MQs.  If the MQ for them is
> false on page load, they shouldn't load at all until the MQ becomes
> true.  I suspect these would have the same null OM until requested.
>
> Is this accurate?
>
> ~TJ
>