[whatwg] Possible compremise for namespaces in html5

Ian Hickson ian at hixie.ch
Thu Feb 11 03:18:57 PST 2010

On Thu, 5 Nov 2009, Rob Ennals wrote:
> I've talked to a few people about the distributed extensibility problem 
> and I'd like to suggest a possible compromise

There are a huge number of "distributed extensibility" problems, many of 
which are already resolved in HTML5. For the purposes of evaluating 
proposals, we must know what kind of problem is being addressed by the 

For the purposes of this discussion, I'll assume the problem being 
discussed is how to include structured proprietary site-specific metadata 
in an HTML page, since if I recall correctly that was the problem being 
discussed at TPAC when you made this proposal.

> * maintain a central registry of prefixes with standard meanings - so eg fb
> always means fbml. Thus no namespace decl is needed.
> * for a prefixed node the prefix is itself the namespace - thus the user agent
> doesn't need to know what a prefix means
> * prefixes are allowed for tags and attributes
> * a web browser MUST ignore prefix tags and attributes - they are for data,
> just like microdata and data attributes, not for browser extensions

It's not clear what this adds that microdata itself doesn't. Could you 
describe a situation in which structured proprietary site-specific 
metadata could not use microdata but _could_ use the above scheme?

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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