W3C home > Mailing lists > Public > public-respimg@w3.org > September 2012

Re: @type attribute on <source> elements

From: David Clements <huperekchuno@googlemail.com>
Date: Fri, 7 Sep 2012 13:21:56 +0100
Message-ID: <CAF8j4Vu9x7P+-hf+KudQpskBp-FUD5EOjFbZuFmX6WrH9UhcAg@mail.gmail.com>
To: Aaron Gustafson <aaron@easy-designs.net>
Cc: "Nathanael D. Jones" <nathanael.jones@gmail.com>, "public-respimg@w3.org" <public-respimg@w3.org>
I've been pondering this as a background process for the past hour or so...

I think I'm seeing the point - by having browser skip an unsupported MIME
on a type attribute it avoids unnecessary HTTP requests and possibly even
broken images whilst allowing developers to specify modern MIME types with
JPG/PNG/GIF fallbacks?

Dave

On Fri, Sep 7, 2012 at 12:59 PM, Aaron Gustafson <aaron@easy-designs.net>wrote:

> On Thursday, September 6, 2012 at 5:21 PM, Nathanael D. Jones wrote:
>
> I'm starting a new thread about the @type attribute, as requested by
> Adrian Roselli.
>
> I believe it is critical that we REQUIRE browsers to SKIP source elements
> which have an unrecognized (or unsupported) mime-type value in the @type
> attribute.
>
> Otherwise, we will not be able to introduce to formats and simplify
> <picture> in the future.
>
> @type should be an OPTIONAL attribute, not required, but if present,
> browsers should handle it in a specific way. Widely supported formats like
> jpeg, png, and gif do not need a type="" attribute, but webp and future
> formats do.
>
> This will allow us to introduce new image formats in a
> backwards-compatible manner.
>
>
> Iím inclined to agree with this proposal, but I do think it's probably
> worth addressing the fact that MIMEs could still be managed server-side as
> well.
>
> If an explicit MIME is supplied, it is probably safe to assume the author
> (or script generating the markup) knows what she is doing, but in the
> absence of one, I would assume a UA should fall back to the server-supplied
> MIME. It's obviously less efficient because the UA would need to at least
> obtain the headers for the file, but if we are addressing the use of the
> type attribute, we should probably provide explicit documentation about the
> fallback in the match algorithm.
>
> Cheers,
>
> Aaron
> --
> Aaron Gustafson
> @AaronGustafson
> aaron-gustafson.com
>
> -------
> Aaron takes no responsibility for poor spelling in this message. It was
> pecked out by fat fingers on a tiny screen.
Received on Friday, 7 September 2012 12:22:30 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 7 September 2012 12:22:31 GMT