W3C home > Mailing lists > Public > www-style@w3.org > October 2007

Re: Proposal of @ua

From: Brad Kemper <brkemper@comcast.net>
Date: Sun, 21 Oct 2007 20:00:20 -0700
Message-Id: <85FDC661-C274-48EC-952A-0E3FD35A0A61@comcast.net>
Cc: WWW Style <www-style@w3.org>
To: David Woolley <forums@david-woolley.me.uk>

On Oct 21, 2007, at 2:57 PM, David Woolley wrote:

> Brad Kemper wrote:
>>   | min-build | max-build | min-version | max-version
> Getting people to update max-version retrospectively is the  
> problem. That's essentially why IE User-Agent strings spoof  
> Netscape, and why
> everyone else, including Netscape(!) spoof IE, in the comment that  
> contains IE's real identity.
> Basically what happens is that the user agent gets updated to  
> remove a restriction, but the legacy web pages (and those cut and  
> paste coded from them) still effectively reject it.  The result is  
> that the browser has to spoof the market leader to get round this.
> The original CSS concept was that unsupported properties were  
> simply ignored, so that they would automatically start working when  
> the browser starts supporting them.  I know this makes pixel  
> perfect designs difficult.
> -- 
> David Woolley
> Emails are not formal business letters, whatever businesses may want.
> RFC1855 says there should be an address here, but, in a world of spam,
> that is no longer good advice, as archive address hiding may not work.

Call me an optimist, but I don't see that as being the same problem  
as with JavaScript, etc. I imagine people would have a basic,  
standards-based css for media=all, and bowser/version limited sheets  
for versions with known problems. It would be much cleaner than the  
current situation, in which long user agent strings are parsed on the  
server to serve browser-specific css, or where hacks are so scattered  
throughout the css file that it is not clear what version of what  
browser they are for, and then they break anyway when a new version  
comes out. At least if it is built into a media query, it is more  
controllable, and has a greater chance of being accurate and  
maintainable than with the current situation.

Today if I want to target Safari 3 I can use a media query that  
starts with "only", and I think Safari is the only one that could  
read it. But then I'd have to change my hacks to something else once  
other browsers become compliant with that standard. Nobody wants  
that. If the ua and renderer values in the media query were limited  
to a single word, then UAs that impersonated a different piece of  
software would do so at their own risk (with very little advantage,  
unless they possessed the same parsing errors as other software), and  
there would not be the squeezing of several words from other browsers  
into the string. By having both a UA and a Renderer value, authors  
could target the problems exactly where they existed and have general  
style sheets for everyone else that assumed near perfect compliance  
with the recommendations.
Received on Monday, 22 October 2007 03:00:27 UTC

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