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Re: [CSS3] pseudo class for "current element"

From: Andrew Fedoniouk <news@terrainformatica.com>
Date: Tue, 25 Jan 2005 17:26:23 -0800
Message-ID: <41F6F1BF.4040502@terrainformatica.com>
To: "L. David Baron" <dbaron@dbaron.org>
CC: www-style@w3.org

Hi, David,

L. David Baron wrote:

>On Tuesday 2005-01-25 15:59 -0800, Andrew Fedoniouk wrote:
>  
>
>>For example: 
>><select> element (list box) is "focusable" element but its <options> are not. 
>>Being in focus, <select> has one current item (option) which is visually distinct from others. 
>>    
>>
>
>The selected option should probably match the :checked pseudo-class.  A
>SELECT is logically pretty much the same thing as a radio group.  
>
>  
>
As discussed month ago in this list :checked corresponds to selected 
state of an <option>
E.g. for <SELECT multiple> it matches any <option selected>.
In short, neither :selection  nor  :checked  cannot be used for :current 
item.

>>I mean it is lack of "containment" selectors like:
>>
>>P < DIV  - any <div> which contains <p> 
>>* < DIV  - non empty div 
>>OPTION:focus < SELECT  - select having option in focus. 
>>    
>>
>
>These have been discussed extensively on this list and one proposal was
>in early drafts of css3-selectors.   Search for ":subject" (the one that
>was in css3-selectors), ":has", and ":matches".
>
>The problem is that they're all difficult to implement effeciently in
>the processing model used for CSS selectors (used via a function that
>maps (element, selector) -> boolean).
>  
>
Proposed "8.3.2 Indirect adjacent combinator" [1] has the same 
computational complexity
as ":has" or "<" - O(n). So, if we will allow to use first why not to 
allow use second?

>(The two bits of your message that I quoted seem like two entirely
>separate issues, although the middle of the message seemed to connect
>them in a way that I didn't understand.)
>  
>
Imagine that <SELECT> is a container of focusable <OPTION>s like <FORM> 
with <INPUT>s.
If SELECT/OTIONs will behave this way we don't need "current element" 
entity - current select element is the one with
the focus. The problem is that sometimes <SELECT> in focus (or having 
focus inside) has different look - e.g. "activated" border or selected 
items in it render in different color, etc.

So to be able to show "styled SELECT" I need either :current selector or 
:has/:match/'<'.  I personally prefer the first option.

Andrew Fedoniouk.
http://terrainformatica.com


[1] 
http://www.w3.org/TR/2001/CR-css3-selectors-20011113/#adjacent-i-combinators
Received on Wednesday, 26 January 2005 01:26:44 GMT

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