[whatwg] Where did the "rev" attribute go?

Ian Hickson ian at hixie.ch
Wed Jul 5 22:23:36 PDT 2006

On Thu, 6 Jul 2006, Tore Eriksson wrote:
> Regarding usage of "rev", I would like to point out the RDF/A proposal
> http://www.w3.org/2001/sw/BestPractices/HTML/2005-rdfa-syntax.html
> where they use "rev" to incorporate RDF into (X)HTML documents.

RDF/A is an utter disaster and not a valid use case for anything. For a 
more detailed comment on RDF/a, see:


> As for myself, I use the "rev" attribute in an internal project (sorry, 
> no link) at work. I have to agree with Charles/Iliya that the 
> recognition of "rev" is probably going up in the future if the adaption 
> of new microformats continues.

It certainly can't go down.

> > On the contrary, I would argue that we should get rid of it as fast as 
> > possible, so that we don't scare away authors who are becoming 
> > "semantically minded" by making the language more complicated than 
> > absolutely necessary.
> I have to disagree here. Removing the complexity in the HTML 
> specification just moves it to the semantic application where the 
> "semantically minded" users have to agree on what the corresponding 
> inverse relations are. In my opinion the HTML spec is the place where 
> this distinction can be kept with the least amount of "interfering" 
> complexity. As your survey shows, there is not a lot of confusion about 
> "rev", just some people having problems with spelling the "rel" 
> attribute. I think there would probably have been a lot of "herf" 
> attributes out there if they were not discovered as easily as they are.

The point is not just that people mis-use the rev attribute; the point is 
that with the exception of a single value ("made"), people *typo the "rev" 
attribute more often than they intentionally use it*.

Another interesting statistic: people use rel="made" once for every 2.2 
instances of rev="made". That is *far* more frequent a mistake than other 
typos (the <script langauge=""> typo, which is so common that it appeared 
in the top-1000 attributes, is only made once for every 833 uses of the 
correct one -- and that's another example, just like rel/rev, where making 
the typo causes no ill effects in browsers, so it is equivalent IMHO).

This, to me, suggests that in fact what you call a simple typo is not just 
a typo, to me it seems to really be author confusion.

> > > As developers start building semantics into web technologies, their 
> > > going find that they need the "rev" attribute.  (Not sure if that 
> > > would be enough "justification" here to keep it.  But since we 
> > > already have it, it would be nice to keep it.)
> > 
> > For HTML5 the assumption is that we're removing everything unless we 
> > can put forward a convincing argument to keep it.
> > 
> > What are the use cases for "rev"? Do they outweigh the author cost?
> See RDF/A.

See above. RDF/a is not a use case.

> What is actually the author cost in keeping the "rev" attribute? 

See above. One mistake for every 2.2 correct uses.

> Wouldn't you say that there is a cost in removing it as well?

Not a significant one. The "rev" attribute is almost never used. Almost 
all uses are actually rev="made", which is a non-issue (it is trivially 
replaced by rel="author" and we can grandfather that usage in if there is 
a tool that requires that information, for back-compat).

> And removing it also contradicts the statement "care has been taken to 
> ensure that backwards-compatibility is retained" in the draft (1.3.)

Preventing future documents from using this attribute does not break 
backwards compatibility.

> Just for reference, what was the usage of the "hreflang" and "media" 
> attribute in anchor tags? At what usage level do you feel it is 
> apropriate to compromise backward compability by removing an attribute?

Removing those attributes wouldn't affect backwards compatibility.

<a hreflang=""> was used about as much as <a location.href="">, <hr 
aligh="">, and <td heigth=""> (around 800th in the chart of top-1000 
attributes in the sample). <a media=""> didn't register. <link 
hreflang=""> came in at around 950th, <link media=""> came in at around 
142nd (stylesheets mean this attribute is oft-used).

hreflang="" and media="" don't seem to cause any author damage. They 
provide a useful hook that can't be done any other way. Thus they seem 
potentially valuable and don't have a high associated cost.

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

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