W3C home > Mailing lists > Public > www-style@w3.org > October 2013

Re: Referring to elements from CSS. (In, but not limited to [css-images-4] and [css-gcpm])

From: Simon Sapin <simon.sapin@exyr.org>
Date: Wed, 02 Oct 2013 09:48:52 +0100
Message-ID: <524BDDF4.50500@exyr.org>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: www-style list <www-style@w3.org>
Le 01/10/2013 23:37, Tab Atkins Jr. a écrit :
> On Tue, Oct 1, 2013 at 1:35 PM, Simon Sapin <simon.sapin@exyr.org> wrote:
>> Hi,
>>
>> We have two drafts with features that refer to an element from the value of
>> a CSS property. They do so with two different mechanisms; I think we should
>> pick one preferred way.
>>
>> * The element() function in css-image-4 takes an ID selector.
>> * The cross-reference functions in css-gcpm such as target-counter() take an
>> URL (which needs to be in the same document and have a fragment identifier.)
>>
>> Even though the two may seem similar (#foo), they are different in syntax
>> (eg. character escaping) and semantics (<a name=foo> is a fragment target
>> but not an ID.)
>
> The syntax is more different than that, actually, since the id
> selector can just be "#foo", while a url has to be "url(#foo)".

Yes.


>> ID selectors are the easiest from a spec point of view: we can just refer to
>> the Selectors spec and we’re done. For URLs however, we need to define how
>> fragments are mapped to elements or refer to something that does. This is
>> probably defined in HTML, but CSS so far is supposed to support any type of
>> document and maybe shouldn’t depend on HTML.
>>
>> URLs on the other hand are very nice for using 'attr(href url)' on link
>> elements. 'target-counter(attr(href url), page)', for table of contents, is
>> a typical use case for target-counter().
>
> I'm fine with defining a more general <element-ref> type, which allows
> both ID selectors and <url>s, which can be used for
> element()/target-counter()/etc.

If we have to deal with defining how fragments map to elements anyway, I 
don’t see a point in keeping ID selectors for this. Unless we want to 
extend this to more selectors later?

-- 
Simon Sapin
Received on Wednesday, 2 October 2013 08:49:22 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 2 October 2013 08:49:22 UTC