canvas 2d context
Encrypted Media Extensions
HTML 5 spec
HTML 5: The Markup Language
HTML WG website
HTML5 differences from HTML4
HTML5 Spec - PR Blockers
Media Source Extensions
pre-LC1 alt techniques
pre-LC1 authoring guide
pre-LC1 HTML 5 spec
Erika Doyle Navara
Philippe Le Hégaret
Joshue O Connor
The HTML5 specification does not have a mechanism to allow decentralized parties to create their own languages, typically XML languages, and exchange them in HTML5 text/html serializations. This would allow languages such as SVG, MathML, FBML and a host of others to be included. At one point, an editors version of the HTML5 specification contained a subset and reformulation of SVG and MathML. Tim Berners-Lee described this incorporation of SVG and MathML without namespaces as horrific and the issue raiser [Dave Orchard] completely concurs with the him.
This issue limits the ability of non-HTML5 working groups to define languages as the languages must be "brought into" the HTML5 language. This dramatically increases the scope of HTML5 and decreases the ability to modularize development of orthogonal languages.
In the end, the problem could result in the text/html serialization rules becoming the standard serialization rules for XML languages, replacing XML itself. This could occur if every decentralized language has a choice between the XML serialization, the text/html serialization or both. In many cases, the language may choose the text/html serialization.
This issue was first raised in August 2007 by Sam Ruby in  and also raised at the recent W3C AC meeting by Tim Berners-Lee 
 http://www.w3.org/2008/Talks/0421-ac-tbl/#(1) (member-only link until Tim publishes in a public way)
HTML5-SPEC-SECTIONS [semantics-0 extensibility]
Add notes (no markup allowed, URIs get automatically hyperlinked):
(Changing this to closed seems to have changed the name of who raised it; not sure what to do about this, David doesn't appear in the list for me.)
I don't think we can make this design decision so blithely, and the justifications of comparing to MARQUEE, BLINK and LAYER are missing part of the point - the decentralized extensibility would be for app/content builders, not for browser vendors.
<rubys> last week ChrisW indicated that he would prefer that that [demote from open to raised] NOT be done. We need to chat (Chris and I).
editor's position seems to be given in
Supporting MathML and SVG in text/html, and related topics
Thu, 10 Apr 2008 09:51:20 +0000
r1399 Fri Apr 4 17:07:36 PDT 2008
[MikeSmith]: initial proposal from Tony Ross is at http://lists.w3.org/Archives/Public/public-html/2009Sep/att-1216/MicrosoftDistributedExtensibilitySubmission.htm
Moved to OPEN state because there is a Change Proposal available.