- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Wed, 16 May 2012 12:00:52 -0700
- To: Matthew Wilcox <mail@matthewwilcox.com>
- Cc: WHATWG List <whatwg@whatwg.org>
It's not that bandwidth queries aren't possible, it's that they're not *useful* for the things you'd want to use them for, and they don't act like you'd want anyway. I explain much of the reasoning in <http://www.xanthir.com/blog/b4Hv0> - while the blog post purports to be about resolution negotiation, it actually more generally covers why bandwidth queries are a bad idea. In short, bandwidth is often quite variable, particularly on the devices where you'd actually *want* to use this information. This means the instantaneous bandwidth (what MQ would be using) can easily be useless to you. It also means that you'll easily and commonly get into perverse situations where trying to be "bandwidth-friendly" ends up downloading *more* data than a naive page would. The author is just not in a good situation to be able to make sound decisions about how to react to bandwidth. You need a lot more information than a MQ can provide, and even if we provided it, the logic necessary to use that information *right* is fairly subtle and definitely not settled. This is why providing facilities for the author to just *tell* the browser about the relative filesizes of things, so it can make its own decisions about which resource to download. This keeps the language simpler, because we don't have to communicate as much information. It also centralizes the "what to do" logic into a small number of places (the browsers) where it has a better chance of being right, rather than hoping that thousands or milions of authors all stumble on the best solution together, and keep their pages updated as best-practices change. ~TJ
Received on Wednesday, 16 May 2012 19:01:49 UTC