[whatwg] [html5] tags, elements and generated DOM
ian at hixie.ch
Thu Feb 23 18:34:00 PST 2006
On Wed, 6 Apr 2005, Lachlan Hunt wrote:
> Ian Hickson wrote:
> > On Wed, 6 Apr 2005, Lachlan Hunt wrote:
> > > > The <body> will always be implied, though.
> > >
> > > Not in a conforming SGML parser...
> > Yeah, I meant in browsers, not per SGML.
> Ok, fair enough. But can you explain why Opera doesn't when in
> standards-compliant mode, as I explained in my previous e-mail. Is it a
> bug or intentional?
> > According to the HTML spec, the handling of the above is completely
> > undefined since it is invalid. (Note that something being invalid or
> > non-conformant does _not_ make the rendering undefined in most cases
> > in Web Apps 1 / HTML5. That's one of the main things I'm making sure
> > of.)
> Ok, if the spec is going to address this, then I think it should say something
> "If a required element with an optional start-tag is entirely missing
> from the document, a user agent *may* imply it and include it within
> the DOM. Missing elements with required start-tags *must not* be
> automatically implied.
It's been defined much more explicitly. Let me know if the current text
doesn't satisfy you.
> "Note: It is common for existing user agents to automatically imply
> both the head and body elements, even when those sections are omitted
> entirely from the document markup."
I haven't included this. Do you think I should?
> I used "may", because if "must" or "should" were used instead, it may
> conflict with anything the SGML spec says on the matter and it would
> make OpenSP, and thus the validator, non-conformant. I would stick with
> "may" because, as I showed previously, existing UAs don't do the same
> for <tbody>.
OpenSP and the validator are already non-conformant to HTML5 for many
other reasons unrelated to parsing (e.g. they don't do attribute value
> I included the part about start-tags because elements like <li> (which
> require a start-tag) do not be implied by existing UAs when they are
Indeed. This is all fully defined by HTML5 now.
> Also, while on the topic of handling invalid documents, is this spec
> going to attempt to address the <x><y></x></y> problem?
Yes, that is covered and fully defined too, using a variation of what
Mozilla and Safari do as the basis for the specification.
> > > Opera and OpenSP correctly don't imply the missing head element.
> > I'm not sure what you mean by "correctly" here
> Well, I read somewhere that OpenSP is "the reference implementation" of
> SGML, so I assumed that means what it does is correct.
So what if the spec and the implementation disagree? :-)
> > since an HTML4 document without a <title> is invalid and thus parsing
> > is undefined in HTML4.
> Is it not defined by SGML either? I really must get a copy of
> Goldfarb's SGML Handbook later and check for sure.
Not as far as I recall, certainly.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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