[uf-discuss] re: HTML5 support

Philip Jägenstedt philipj at opera.com
Tue Jul 20 05:07:49 PDT 2010

On Tue, 20 Jul 2010 13:05:56 +0200, Ciaran McNulty  
<mail at ciaranmcnulty.com> wrote:

> On Tue, Jul 20, 2010 at 5:05 AM, Angelo Gladding <angelo at gladding.name>  
> wrote:
>> Can an enlightened soul describe in which ways microdata is actually
>> superior to profiled poshformats?
> To me it's not a question of Microdata vs POSH, it's more like
> Microdata vs class attributes where both are methods that can be used
> in POSH style data embedding.
> The main arguments (and I present these without necessarily agreeing!)
> seem to be:
> 1. Class is ingrained as a CSS hook mechanism. Most people on this
> list are fine with class being used for other purposes, but despite
> that the argument comes up incredibly often that using class is
> somehow a 'hack'. Microdata overcomes that, so right or wrong, it may
> be worth ditching class for embedded data just to help uptake.
> 2. The class space is already populated with lots of ill-thought-out
> CSS identifiers. This means POSH formats have to attempt crude forms
> of namespacing (e.g. picking a uniquely-named root element) to try and
> not collide with existing markup. That works for @class="fn" say, but
> it's easy to collide with @class="email". Microdata separates out the
> important stuff.
> 3. Related to 2, microdata extraction is possible without having to be
> profile-aware, so for instance microdata can be converted to JSON
> without knowledge of the vocabulary used.
> 4. Microdata features some structures like @itemref that help combine
> disparate data across a document into one Microdata element, which in
> Microformats would need the slightly hacky rel-include structures that
> frankly I don't think anyone has been completely happy with.
> 5. Microdata allows locally-scoped typing using the @itemtype property
> and a URL, while a POSH format can only do something similar with a
> document-level @profile.
> 6. Microdata defines an API for DOM access to Microdata that allows
> scripts to deal with Microdata-embedded data when doing the same with
> Microformats involves some fairly heavy DOM parsing.

Well written. Unlike yourself, I agree with all of the above :)

> The arguments against Microdata are basically that it's complex, huge,
> obviously isn't based on any existent markup in the wild, and really
> doesn't look like an obvious core element of HTML5 so it's weird that
> it's included in the same spec.

Well, it's not in W3C's version of HTML5, they published it as a separate  
spec (which is strange, IMO). Regardless of what spec it is in, it still  
works just the same, so that's OK.

Philip Jägenstedt
Core Developer
Opera Software

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