W3C home > Mailing lists > Public > public-html@w3.org > January 2009

Re: HTML is a declarative mark-up language

From: Leif Halvard Silli <lhs@malform.no>
Date: Sat, 31 Jan 2009 00:24:39 +0100
Message-ID: <49838C37.7010907@malform.no>
To: Boris Zbarsky <bzbarsky@MIT.EDU>
CC: Robert J Burns <rob@robburns.com>, HTML WG <public-html@w3.org>

Boris Zbarsky 2009-01-30 22.32:
> 
> Robert J Burns wrote:
>> You're honing in on what I was talking about now. There are reasons to 
>> have an element that says this is here solely as a anchor destination. 
>> A 'span' with an 'id' attribute might be there for some particular CSS 
>> hook. However, a phrase wrapped in an "a" with only an 'id' and no 
>> 'href' is clearly an anchor destination.
> 
> I guess I'm at a bit of a loss to think of a situation where something 
> is solely an anchor destination without having any other semantics.

In Wikipedia (e.g. see http://en.wikipedia.org/wiki/Anchor ) you 
find things like this:

<p><a name="Anchoring_gear" id="Anchoring_gear"></a></p>

When you look at the code, you are in no doubt of the purpose of 
that element there: it is solely there for the purpose of linking 
to it.

> Anything I can think of linking to directly as part of a document 
> (sections, images, lists, tables, <pre> blocks with program code, 
> quotations, etc) all have appropriate semantic tags that one would need 
> around the thing being linked to anyway...  At that point, it might be 
> more clear to put an ID on said semantic tag and use that as the anchor 
> destination.
> 
> Maybe there are situations I'm just failing to think of here?

May be - I speculate - it is more easy to add an empty anchor 
element rather than manipulating the id of a container element? 
After all, in Wikipedia, the id-refs, and hence the links, will 
change very very often.

[ I only have one HTML editor available that is able to 
automatically coordinate id attributes (of h1-h6 elements) with a 
ToC, and that is Amaya. So may be there is some problem there ... ]

Also, if I want a place to be a destination anchor, without having 
  to investigate or find out (it may be impossible to know the 
content of the A element if it is generated via DOM etc) the 
*further* semantics of the anchored resource, then I can use <a 
id="ref">resource</a> and be certain that I have at least not lied 
plus that I solved a practical problem.

>> Similarly any id can serve as a anchor destination, but an 'a' element 
>> with an 'id' alone is clearly an anchor destination. This is signaled 
>> to any other authors of the document in a way that a 'span' element 
>> with an 'id' attributes does not signal.
> 
> While true, it also leads to this fairly common HTML4 authoring pattern 
> (with name replaced by id on the <a>):
> 
>   <a id="mytable"></a>
>   <table><tr><td>
>     This is an important table that people should link to
>   </td></tr></table>
> 
> both because authors copy/paste from existing HTML (which is informed by 
> the HTML 3.2 legacy of not being able to link to IDs) and because the 

At least copy-paste is not the reason in Wikipedia.

> spec gives <a> a privileged status as an anchor destination that 
> obscures the fact that any element can be an anchor destination if 
> that's what you're really meaning to link to.

I cannot really agree that HTML 4 gives a privileged status to the 
A element. Except for the way that name="" allows the full unicode 
"alphabet" to be used as name content. HTML 5 will be based on 
IRIs, so that there is no reason for using name="" for that reason 
anymore.

That is a element that is singled out for one purpose has nothing 
to do with "privileged status".

> Note that the above example would break badly if someone happens to 
> apply a style that positions the table away from the anchor.  So it's 
> not just a matter of semantic purity being violated (thought it most 
> certainly is), but of practical consequences that make the document less 
> robust than it could be.

However, if I have gotten it right, in HTML 5 it will be 
non-conforming to e.g. write

<body><inline-elemetn></inline-element></body>

(or has that idea been left?)

>> It is dropped from document conformance. The use of an 'a' element 
>> with only an 'id' attribute that is also relevant is not supported in 
>> the current HTML5 draft (but it has been supported in XHTML1.1, 
>> XHTML1, HTML 4.01, so why are we changing it?).
> 
> I agree that this is a good question.  It seems to me that while the use 
> of such an <a> should be conformant, it should be given no special 
> status as an anchor destination, for the above-described reasons.

How would you take away the special status, I wonder ... After 
all, it only has two purposes - anchored link or link anchor.
-- 
leif halvard silli
Received on Friday, 30 January 2009 23:25:21 UTC

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