Bob Wyman wrote:
>Sjoerd Visscher wrote:
>
>
>>[HTML 4.01 says:] This attribute describes the relationship from
>>the current document to the anchor specified by the href attribute.
>>The value of this attribute is a space-separated list of link types.
>>
>>
> But, if you copy HTML from one document to another, or you construct
>an HTML document from parts, you risk carrying <a> tags with rel attributes
>from one document to another. If I quote some HTML in a new HTML document
>and the quoted HTML includes rel="alternate" in an <a> tag, are we really
>saying that the presence of rel="alternate" in the quoted text establishes a
>relation of the new HTML document as a whole?
> Personally, I think there is a serious scoping problem here. We've
>got attributes of separable components of a page establishing metadata for
>the page as a whole. Not good.
>
> bob wyman
>
>
Since the HTML spec is where this originates, I'm inclined to say that
this is something that should be handled by whatever is manging content
(user or program) is copying the link. Clearly, @rel should be copied
with caution or simply left behind entirely.
I think calling this "components of a page establishing metadata for the
page as a whole" is a bit misleading. The metadata (@rel) say nothing
about the document it's in. It's metadata about the link between the two
documents. This metadata is context-Dependant because it depends on an
implicit @from counterpart to the explicit @href (@to, in XLink).
<link> and <a> both suffer from this weakness. I can't pick up a link
element from one element and move it to another. I can have a pile of
them in the template I use to make my pages.
It's considered a usability problem in the case of <a> because <a>
appears in a place where it's a it more likely to be copied: the body.
The problem is fortunately mitigated because user agents usually only
offer copying @href ("copy link location"). I'm under the impression
that they do something similar with rich-text copying. If someone's
copying HTML "source" by hand, then they should know to be wary of @rel.
The best we can do is add a note.
It's also not likely to bother programs that put content into
syndication feeds because links to feeds generally appear in the
periphery of presentation and not the main content of a feed. If people
do include @rel in content that's included in syndicated content, then
it should be stripped.
Again, no one uses @rel in <a> because it's unsupported. Coincidentally,
most programs do the right thing. If we push for @rel support in <a> in
the autodiscovery spec, then I think there may be an increase in usage,
at which time users can authors can educate themselves and programs can
make changes. They should have done this years ago. We're not creating
@rel, just encouraging it's use.
All of that said, it seems sensible to include a warning or a note or
somesuch.
-Nikolas 'Atrus' Coukouma
