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Re: Parent Combinator / Parent pseudo-class

From: Francois Remy <fremycompany_pub@yahoo.fr>
Date: Fri, 25 Jul 2008 12:35:25 +0200
Message-ID: <F67E953499B44BBEB35C5C3C4787760E@FremyCompany1>
To: "Andrew Fedoniouk" <news@terrainformatica.com>
Cc: "Boris Zbarsky" <bzbarsky@MIT.EDU>, "www-style list" <www-style@w3.org>

From: "Andrew Fedoniouk" <news@terrainformatica.com>
>
> Francois Remy wrote:
>>
>> From: "Andrew Fedoniouk" <news@terrainformatica.com>
>>>
>>> Francois Remy wrote:
>>>>
>>>> Yes, there's another solution : you can watch change applied on the 
>>>> elements that can change the value of the rule.
>>>> But it's not possible to know when an element changes in JScript...
>>>
>>> Imagine that I you have some event that is fired when one of its
>>> attributes, states or its subtree is getting changed.
>>> (Lets put aside for the second when such an event needs to be fired)
>>>
>>> How it will help you?
>>
>> You don't need to run the whole selector each time there's a DOM 
>> modification, only each one that are applying on elements that are 
>> concerned by the rule.
>
> First:
>
> Let's say for the selector:
>
> html:with-child(a:hover) p
> {
>   border: 1px solid green;
> }
>
> what would be the mechanism that does "only each one
> that are applying on elements that are concerned by the rule"?

The document must be hooked :
- Each time a new element is added to the DOM, we must check if it match the 
rule

Any HTML element must be hooked :
- Each time a new element is added to the DOM, we must check if the HTML 
element now match the rule (a:href added) or if it match a rule (a or p)

Any A element of the HTML element must be hooked :
- Each time an element get of loose :href, we need to check if the HTML 
element now match the rule

Any P element of the HTML element must be hooked :
- No condition here, but if it was P[title], we should check each time the 
title attribute is modified on a P element child of HTML to see if it match 
the rule

>
> Second:
>
> Consider these two selectors:
>
> p
>   {
>     border: none;
>   }
>
> html:with-child(a:hover) p
>   {
>     border: 2em;
>   }
>
> and markup:
>
> <html>
>   <p><a href="*">sample</a></p>
> </html>
>
> In such case selector above will never be true
> if to assume that computation of selectors happens instantly.
>
> On real world PCs with finite time needed for computation you
> will see nice oscillation.

a { display: block }
a:hover { display: none; }

And this one ? Bad use of :hover selector is not linked to with-child.

>
>
> -- 
> Andrew Fedoniouk.
>
> http://terrainformatica.com
> 
Received on Friday, 25 July 2008 10:36:04 GMT

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