[whatwg] Proposal for change in recommendation for loading behavior of non-applicable stylesheets

Boris Zbarsky bzbarsky at MIT.EDU
Mon Jun 11 14:20:12 PDT 2012

On 6/10/12 11:26 PM, Scott Jehl wrote:
 > These are fair answers, but I can't help but think that the problem
 > is critical enough to warrant spec-level consideration.

Oh, yes.  The question is how to spec this in a way that doesn't 
overconstrain future implementations to behave suboptimally.

 > I think you've rightfully pointed out that the lazy-loading idea
 > probably won't fly with vendors and could even cause problems in
 > certain cases.

I think it would be quite doable and the spec should be changed to allow 
it.  I'm just not sure that the spec should _require_ it in all cases, 
because we can end up in situations where simply detecting whether 
something should be lazy-loaded or not is more expensive than just 
loading it.

 > Even assuming that implementing this feature would mean delaying CSS
 > prefetching until the metaviewport tag was parsed, wouldn't the
 > tradeoff in page loading speed be worth it?

It depends on the use cases....  Consider a page that has no <meta 
viewport> at all (i.e. most of them).  Your proposed change right above 
would disable CSS prefetching altogether on such a page, which is pretty 

 > Thanks again and if you feel this isn't the proper forum for
 > addressing this issue, do you have any suggestions where I should
 > take it?

This list is the right forum.


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