Re: [Fwd: Re: ISSUE-41: Decentralized extensibility]


I think Ian is correct, his example will look different. I don't think it's possible to avoid breaking at least some broken examples.

However, it's possible that we could reformulate our proposal to break out as soon as a starting tag is found that is unknown, or on elements that are known to be in the html language. This breaks some other things however. Try replacing the <p> with <a>. Now how would you expect it to be handled? Or if it was preceeded by an element <metadata xmlns="">?

In the example the author has clearly indicated that an svg is expected there. Now, if that svg fragment was broken, it does its best effort to recover, but it's not possible to repair each and every case of breakage. Not in this proposal, and not in the the proposal made by the HTML WG.


On Wed, 23 Jul 2008 07:24:35 +0200, Doug Schepers <> wrote:

> Hi, SVG WG-
> On the subject of decentralized extensibility, Hixie made the following
> comment.
> Either he misunderstands our proposal, or we do.  Obviously, the goal
> would be that the page would still render the HTML, but that no SVG
> would be rendered.  Is there a flaw with our proposal, either in the
> technical details or in the way we've described it, or is he merely
> misunderstanding it (or mischaracterizing it)?
> Regards-
> -Doug
> -------- Original Message --------
> Mon, 21 Jul 2008 22:26:35 -0700 (PDT)
> Date: Tue, 22 Jul 2008 05:26:35 +0000 (UTC)
> From: Ian Hickson <>
> To: Doug Schepers <>
> Cc: HTML WG <>
> Subject: Re: ISSUE-41: Decentralized extensibility
> On Mon, 21 Jul 2008, Doug Schepers wrote:
>> You cite a few cases of strange mixed-namespace content.  You don't show
>> how this content would break the site as dramatically as you claim in
>> your scenario.  Please draw the connection, if one exists, between your
>> evidence and your conclusion.
> I'm assuming you are really asking "how would a particular proposal fail
> when exposed to the existing content?".
> Well for instance if a page looks like the following (I'm doing this from
> memory but this is quite similar to some of the pages I saw in some of my
> research):
>     <html>
>      <head>...<head>
>      <svg xmlns="">
>      <p>Hello world
>     </html>
> ...then in today's browsers, the page would just say "Hello world". Now if
> we instead use the proposal that the SVGWG has put forward, for instance,
> the page would no longer say "Hello world", it would instead either show a
> blank page or say something like "tml>" or "html>", depending on exactly
> how we define where the XML parser fails. That's an example of this
> proposal "breaking" a page -- the page would look significantly different
> in a browser that implemented the proposal than in a browser that did
> not, despite the page being written before the proposal existed.

Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog:

Received on Wednesday, 23 July 2008 13:44:12 UTC