W3C home > Mailing lists > Public > www-style@w3.org > August 2012

Re: [css4-images] First draft of css4-images, feedback requested

From: Sebastian Zartner <sebastianzartner@gmail.com>
Date: Mon, 20 Aug 2012 07:02:04 +0200
Message-ID: <CAERejNYQQOyaAzrjDV751SPmpn0kgyomcxdeWa5UgZX12eN0bA@mail.gmail.com>
To: Andy Davies <dajdavies@gmail.com>
Cc: www-style list <www-style@w3.org>, "Tab Atkins Jr." <jackalmage@gmail.com>
> > Though when it's about saving bandwidth it makes much more sense to
> decide considering the actual file size rather than the image's resolution,
> which can be easily fetched via HEAD requests. So in the example above
> there would be three HEAD requests. The first one would response that the
> Content-Length is 1000000, the second is 500000 and the third 150000 and
> the user agent with the slow connection would choose the last one instead
> of the first one.
> >
> I'd say it's about the user experience rather than saving bandwidth and
> performing a HEAD request for each image would have a negative effect in it.
> A TCP connection would be tied up for the duration of each request, when
> they could be being used to retrieve content the user will actually see.
> At mobile latencies: 1/3 + secs RTT, the delay of each request would slow
> things further.
> I'd guess the pre-fetcher would probably have problem with multiple HEAD
> requests, and as the pre-fetcher has been responsible for a lot of
> improvement in page load times, I think we need to avoid breaking it if we
> can.
Ok, so we have risking big overhead due to incorrect usage plus redundancy
against overhead due to loading latencies on the negative side. And on the
positive side we have no additional network requests against no risk for
incorrect usage.

Received on Monday, 20 August 2012 05:02:31 UTC

This archive was generated by hypermail 2.4.0 : Friday, 25 March 2022 10:08:20 UTC