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Re: 3.1 Introduction (Draft), review of

From: Philip Taylor <philip@zaynar.demon.co.uk>
Date: Tue, 17 Jul 2007 13:12:04 +0100
Message-ID: <469CB214.9020906@zaynar.demon.co.uk>
To: Robert Burns <rob@robburns.com>
CC: public-html@w3.org

Robert Burns wrote:
> On Jul 16, 2007, at 10:00 PM, Robert Burns wrote:
>> On Jul 16, 2007, at 9:44 PM, Philip Taylor wrote:
>>> Robert Burns wrote:
>>>> First, I think there's a danger of going into too much detail  
>>>> regarding optional tags. The only things I think might need to be 
>>>> in  an introductory section (maybe) are:
>>>> 1) that empty elements must have their closing tag omitted unless 
>>>> an  author uses the xml-style self-closing tag (e.g., <link />).
>>>> 2) that empty elements must be closed when using the xml  
>>>> serialization: i..e., either (<link></link> or <link />)
>>>> So to avoid this confusion and simplify things, it may make sense 
>>>> to  always recommend (or as far as this introduction goes, just 
>>>> gloss- over the difference so that authors use) the self-closing tag 
>>>> for  empty elements.
>>>
>>> Teaching authors about XML-style self-closing tags is also a cause of 
>>> confusion.
>>
>> Just to clarify, when I wrote "empty elements", I meant canonically 
>> empty elements (i.e., elements required to be empty). Yes, I agree 
>> that encouraging the shortcut everywhere be a bad thing for the 
>> text/html serialization. I don't think any of your following examples 
>> relate to that.
> 
> What I meant to say here is that none of the examples relate to the 
> elements with empty content models and that the examples you listed are 
> specifically elements that do not have empty content models. I think we 
> if advised authors to use the self-closing tag on elements with empty 
> content models (and highlighted how the chapter shows those at the 
> beginning of each section/subsection), that would be a simple guideline 
> to follow (for an introductory section). Getting into more detail than 
> that right there (e.g., discussing differences between xml and non-xml 
> serializations) would be counter-productive.

http://www.w3.org/TR/xhtml1/#guidelines already gives that advice:

     "Include a space before the trailing / and > of empty elements, 
e.g. <br />, <hr /> and <img src="karen.jpg" alt="Karen" />. Also, use 
the minimized tag syntax for empty elements, e.g. <br /> ..."

     "Given an empty instance of an element whose content model is not 
EMPTY (for example, an empty title or paragraph) do not use the 
minimized form (e.g. use <p> </p> and not <p />)."

The point of the examples is that people half follow that advice, but 
then they get confused between real XML and HTML-that-looks-like-XML, 
and they forget the distinction between empty content model vs empty 
content, and they end up writing buggy HTML. Advising authors (whether 
in this document or elsewhere) to write HTML-that-looks-like-XML will 
only increase that confusion and result in more broken HTML documents.

> Take care,
> Rob

-- 
Philip Taylor
philip@zaynar.demon.co.uk
Received on Tuesday, 17 July 2007 12:12:35 UTC

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