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Re: Default value of "preload" attribute

From: Robert O'Callahan <robert@ocallahan.org>
Date: Thu, 25 Mar 2010 22:02:29 +1300
Message-ID: <11e306601003250202p3e0a74cbmdd31c26fca891478@mail.gmail.com>
To: Ian Hickson <ian@hixie.ch>
Cc: public-html <public-html@w3.org>
On Thu, Mar 25, 2010 at 9:41 PM, Ian Hickson <ian@hixie.ch> wrote:

> On Thu, 25 Mar 2010, Robert O'Callahan wrote:
> > I actually think that leaving the missing value default up to the UA is
> > a mistake. The difference between "auto" and "metadata" for user
> > experience is often going to be significant. I wonder if other
> > implementors actually want their missing value default to be "auto"?
> Given that pretty much the entire attribute's handling is UA-defined, I
> really don't see much point in making the default defined. Certainly I
> don't think it makes sense to make the default be something that
> explicitly cannot be to download everything, since if that's what the user
> wants, that's what the user should get.

I agree that users should be able to override the default. However, what UAs
default to in the absence of user overrides is what's important, since that
will determine majority behavior and the issue I'm worried about here is
masses of users unexpectedly consuming resources.

However I don't mind changing the suggestion. What do browsers generally
> default to? If most browsers default to metadata, there's not much point
> suggesting auto. :-)

Firefox defaults to "metadata". I believe that's the safe option for authors
who aren't sure what they're doing.

> One more thing ... the resource fetch algorithm says that when
> > preload="metadata" UAs should stop loading after the first frame
> > (HAVE_CURRENT_DATA). Shouldn't that value be named "firstframe" (or
> > something else) then? It's pretty confusing to have preload="metadata"
> > not stop after the metadata has loaded.
> Yeah, the name is mildly misleading. I considered "firstframe" but it
> didn't really seem in the style of the Web platform, insofar as the Web
> has a style. It's not really that confusing; it's not like authors are
> going to say "goodness, why is it that it downloads up to the first frame
> instead of stopping 512 bytes earlier at the end of the metadata?". In
> fact you could even argue that for many purposes (e.g. filling in the
> poster frame if poster="" isn't provided) the first frame is a kind of
> metadata anyway.

I don't really understand why "firstframe" isn't "in the style of the Web
platform". Loading the first frame can consume an order of magnitude more
data than loading the metadata. Mainly though, I'm concerned that authors
will want to preload up to the first frame and will think "hmm, I can
preload up to the metadata, but how do I preload up to the first frame?" But
I don't care all that much.

"He was pierced for our transgressions, he was crushed for our iniquities;
the punishment that brought us peace was upon him, and by his wounds we are
healed. We all, like sheep, have gone astray, each of us has turned to his
own way; and the LORD has laid on him the iniquity of us all." [Isaiah
Received on Thursday, 25 March 2010 09:03:03 UTC

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