Re: assorted HTML and SGML questions
Sat, 18 Nov 95 23:30:22 EST

I was going to reply privately, but some of this might be useful to others,
and I don't have al the answers ;-)

> Q: (("text/html" Internet Media Type)) Does text/html forbid including the
> SGML declaration (<!SGML ...>)? I know it forbids including a document
> type declaration subset, but the standard is unclear on whether the
> SGML declaration is allowed.

This should be fixed -- it's not allowed.

> Q: ((Internet Media Types for SGML))
SoftQuad Panorama uses text/x-sgml -- see for more info.

> Q: ((HTML and Empty P Elements)) What are the semantics of an empty P
> element in HTML? The standard doesn't really seem to deal with this.

If by an empty P you mean
then what do you want the RFC to say?
If you mean the use of <P> without a </P>, a conforming application inserts
the </P> automatically at an appropriate place, as determined by the

> Q: ((SGML Mixed Content)) I'm not sure if I understand the mixed content
> rules properly. Let me state what I guess the rules are so that you
> can tell me if I got it right or wrong. Here is what I think the rules
> are:
> * If a content model contains #PCDATA anywhere, the the entire
> element has "mixed content".
No, only if the element can contain both elements and #PCDATA.

> * If an element does _not_ have mixed content, then a sequence of
> characters between two tags that is solely composed of whitespace
> (SPACE, TAB, RS, RE) is ignored, otherwise the whitespace is
> treated as ordinary data characters and must correspond to an
> occurrence of #PCDATA in the content model.
> Is this right?
Yes. Actually, RS/RE processing is more complex than that; send a message
to to get a paper on Record Start and End in SGML if
you are writing software to deal with it.

> Q: ((SGML LITLEN)) Is the SGML limit on attribute value lengths (LITLEN)
> applied to the attribute value after parsing and entity replacement or
> before?

dunno. Sorry. My references are in the office and I'm at home, and
it's snowing too much for barefooted Liam :-)

> Q: ((HTML PRE Containing FORM)) RFC 1866 says this:
> For example, a <PRE> element may contain a <FORM> element, ...
> This doesn't make any sense because it contradicts the DTD given in the
> same document. What's the story here?
Probably an error in the DTD.

> Q: ((HTML INPUT and SELECT Attributes)) Why is the SIZE attribute of the
> INPUT element specified to have type CDATA while the SIZE attribute of
> element SELECT is specified to have type NUMBER? Is this to allow
> dimension units to be specified? It doesn't say in the standard.

No answer, sorry.