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Re: CDATA, Script, and Style

From: Jonas Sicking <jonas@sicking.cc>
Date: Thu, 2 Apr 2009 12:56:21 -0700
Message-ID: <63df84f0904021256x6b87b2bfv9380333f63d17a15@mail.gmail.com>
To: James Graham <jgraham@opera.com>
Cc: Henri Sivonen <hsivonen@iki.fi>, Simon Pieters <simonp@opera.com>, Doug Schepers <schepers@w3.org>, HTML WG <public-html@w3.org>, "www-svg@w3.org" <www-svg@w3.org>
On Thu, Apr 2, 2009 at 8:16 AM, James Graham <jgraham@opera.com> wrote:
> Jonas Sicking wrote:
>
>> I think that is mostly an orthogonal issue. But I would like <![CDATA[ ]]>
>> in to be parsed as in XML both in foregin content mode, and in normal mode.
>> To keep things consistent.
>>
>> Opera has done experimenting with supporting <![CDATA[ ]]> in HTML and it
>> seems it does not "break the web".
>
> My understanding is that this is not really true; we enabled it for a while
> but will most likely remove support in the future as it proved to have
> significant costs (site compatibility, extra code) and comparatively fewer
> benefits.

You bring up three downsides with supporting <![CDATA[]]> in HTML:
* site compatibility
* extra code
* comparatively fewer benefits

Two of these three seems like they would disappear when implementing
the current draft of HTML5.

There shouldn't be any extra code since we have to support
<![CDATA[]]> in foreign content. In fact, it should be a less code
since we can share more code between the "in foreign content" and
"normal" modes.

There is now the added benefit for users of more consistency between
foreign content mode and normal modes.

However, the site compatibility problem is still there for sure. It's
something we would need to look in to. I got the impression from Simon
Pieters in [1] that adding support for <![CDATA[]]> had not caused
significant site compatibility problems. But he also suggests doing
more research which I think is a very good idea.

Of course, if we could get away with not supporting <![CDATA[]]>
anywhere, not even in foreign content mode, without breaking the
ability to copy XML-SVG and XML-MathML into HTML, then I would be for
that as well. But we'd have to gather data on how common it is to use
<![CDATA[]]> outside <style> and <script> in SVG and MathML before we
can really evaluate that.

I think it would be a net loss for everyone if <![CDATA[]]> only
worked in foreign content mode.

/ Jonas

[1] http://lists.w3.org/Archives/Public/public-html/2009Mar/0241.html
Received on Thursday, 2 April 2009 19:57:13 GMT

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