Re: CSS3 missing selector

On Mar 23, 2009, at 6:15 AM, Giovanni Campagna wrote:

> 2009/3/23 Dave Smith <smithd7@tcd.ie>:
>> Hi www-style
>>
>> I believe there is a useful and yet missing selector. I'll explain  
>> by a
>> rough example:
>>
>> <section>
>> <h1 or h>My section heading</h1 or h>
>> <p>Para</p>
>> <p>Para</p>
>> <p>Para</p>
>> <p>Para</p>
>> </section>
>>
>> Given the above, to style the section content so that it is  
>> indented by
>> 20px, but leave the heading with no margin can be done with:
>>
>> ..section > *:not(h1) {margin-left:20px;}
>
> You could also use ".section > p"

Not unless you are sure that all of the block-level content at that  
level is going to be paragraphs, on all of the pages you apply the  
style sheet to.


> (or negative margins, or text-indent, but this is not relevant to  
> the selector)
>
>> but what if the following could be done:
>>
>> h1:content {margin-left:20px;}
>> A pseudo element wraps the content, based on heading scope, and is  
>> then
>> styled.
>>
>> and
>>
>> h1:section { }
>> A pseudo element wraps the heading and content, based on heading  
>> scope, and
>> is then styled.
>
> 1) Pseudo-elements use two colons: "::section" and "::content"
> 2) It should always be avoided having pseudo-elements targeting real
> elements (instead of CSS generated ones)

It could just as easily be a CSS generated wrapper that was more  
similar to h1:content , but also included the heading.

> 3) Something similar to this was already proposed [1]:

Usually when the same general idea keeps coming up from different  
people, it is because there is a perceived need or benefit.

> :heading(<level>)
> pseudo-class to select elements that estabilish an heading at that
> level (according to the relative language)
>
> :section(<level>)
> pseudo-class to select elements that estabilish a section at that
> level (according to the relative language)
>
> For example, :heading(2) matches "h2" or  "section > section > h" in  
> XHTML2
> :section(1) matches "body" in HTML5
>
>> Apart from being easy to read, one possible advantage is in backwards
>> compatibility with old documents (without section elements) that  
>> they could
>> be styled just as easily as new ones. Plus it just feels good, at  
>> least to
>> me.
>
> Well, old documents don't use new features, so they won''t get much
> benefits from this.

Sure they do. All the time. It is often possible to have a new CSS  
file when it is not possible to replace all the HTML on an entire site.

>> all the best
>> Dave
>> ---
>> Dave Smith, 01 896 3976, smithd7@tcd.ie, Trinity Web Office
>> Please CC the Web Office, webdes@tcd.ie, in correspondence
>> Please note that electronic mail to, from, or within the College  
>> may be the
>> subject of a request under the Freedom of information Act
>>
>
> Anyway, Selectors Level 3 is currently a Last Call WD, so new features
> won't be accepted. You should wait until Selectors Level 4.

Its not too arly to start making a list of things we'd like to see in  
Selectors Level 4, is it?

>
>
> Giovanni
>
> [1] http://lists.w3.org/Archives/Public/www-style/2008Nov/0453.html
>

Received on Monday, 23 March 2009 15:53:32 UTC