[whatwg] Web Forms 2.0 Feedback

Ian Hickson ian at hixie.ch
Wed Apr 13 04:20:27 PDT 2005

On Fri, 7 Jan 2005, dolphinling wrote:
> "green" is just as meaningful as "subscript"--they're both purely 
> presentational, and we as people have attached meanings to certain 
> presentations. The semantics of "subscript" are completely different 
> from the semantics of "there are two of the (chemical) element that 
> immediately preceded this", but we have attached one to the other.

There are some differences:

 * The semantic of <sub>/<sup> can often be deduced from context 
   (especially if we define some specific contexts, like "sub inside var
   means it's the variable's subscript, as in the part of its name that
   identifies the specific variable in a family of variables").

 * There are rarely, if ever, any semantics associated with a colour
   that can be understood without an explanation in the same document.
   Sometimes some content is coloured so that it can be differentiated,
   as in making test results red or green for different results, but
   that is always explained in the same document (if it is to be
   understood, anyway) and is rarely the only aspect of the document
   that indicates the difference (e.g. typically in such an example it
   would be the words "pass" and "fail" that were coloured).

I would love to be able to unambiguously have the semantic for the "2" in 
"H<sub>2</sub>O". I don't see how to do it (at least not without 
introducing a ridiculous number of elements to HTML). I consider <sub> to 
be an acceptable (semantic) compromise. It does affect media other than 
visual media, which (as previously mentioned) is the criteria I usually 
use for working out if something is semantic or presentational.

Another criteria is "could the presentation be changed without losing its 
meaning?". For example, with <em> clearly you can change the presentation 
without losing the fact that it is emphasis: whether it is bigger or 
italics doesn't make much difference. But with <sub> I don't think you 
can. If you change the presentation of <sub> you _do_ change the perceived 
meaning of the rendered content.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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