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Re: Parent Combinator / Parent pseudo-class

From: Francois Remy <fremycompany_pub@yahoo.fr>
Date: Wed, 23 Jul 2008 23:24:32 +0200
Message-ID: <F4717E9E98984A6B8DBDDC915A271834@FremyCompany1>
To: "Brad Kemper" <brkemper@comcast.net>, "Boris Zbarsky" <bzbarsky@MIT.EDU>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, "www-style list" <www-style@w3.org>
Sorry, I missed the attachment.

Note : it only works with browsers that supports querySelector and 
querySelectorAll.
I know IE8 support it and I think Webkit support it too in new release, but 
I'm not sure.

http://www.w3.org/TR/selectors-api/#documentselector

Fremy

--------------------------------------------------
From: "Francois Remy" <fremycompany_pub@yahoo.fr>
Sent: Wednesday, July 23, 2008 11:11 PM
To: "Brad Kemper" <brkemper@comcast.net>; "Boris Zbarsky" <bzbarsky@MIT.EDU>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>; "www-style list" 
<www-style@w3.org>
Subject: Re: Parent Combinator / Parent pseudo-class

> JScript / ECMAScript is very slow in comparaison of C++ or some other 
> native language.
> But I've done the test-case, any way. But it's only to give an idea of 
> that.
>
> ------------------------
>
> Here's a first try to make pseudo-code about it.
>
>    before-selector el-selector.with-child(child-selector) after-selector {
>        color: green;
>    }
>
> ------------------------
>
> The way an element may be found as matching the rule is explained in a 
> previous mail.
>
> As you've got the possiblity to see, it's not much longer than a normal 
> request
>
> -------------------------
>
> But, when must we reevaluate the property ?
> - When any element that's a step of the before-selector change
> - When the element matched by "el-selector" changes
> - When any element that's a step of the first match returned by 
> "child-selector" change
> - When any element that's a step of the after-selector change
>
> So, what's different with a nomal request such as "before-selector 
> el-selector after-selector" ?
>>>> The only thing that's different in rule revalidation is that any 
>>>> element that's a css parent of the first element matched by 
>>>> "child-selector" must also be hooked.
>
> So, we only get a few more "rule revalidation sources"...
>
> ------------------------
>
> In fact, I don't think it's much complex to implement for a respectable 
> UA....
>
> ------------------------
>
> Fremy
>
> --------------------------------------------------
> From: "Brad Kemper" <brkemper@comcast.net>
> Sent: Wednesday, July 23, 2008 6:43 PM
> To: "Boris Zbarsky" <bzbarsky@MIT.EDU>
> Cc: "Tab Atkins Jr." <jackalmage@gmail.com>; "www-style list" 
> <www-style@w3.org>
> Subject: Re: Parent Combinator / Parent pseudo-class
>
>>
>>
>> On Jul 23, 2008, at 9:21 AM, Boris Zbarsky wrote:
>>
>>>> The use-cases have already been noted, and are relatively significant
>>>
>>> I don't think anyone is debating it.  What UA implementors are  saying 
>>> is that they haven't thought of a good way to implement it  yet without 
>>> crippling performance of DOM mutation, and they aren't  willing to 
>>> cripple that.
>>>
>>> -Boris
>>
>> Can you post a test case, using JavaScript to simulate this, to show  how 
>> slow? Where one element with a child is thus selected? Computers  are 
>> pretty fast these days, and I have doubts about how crippling slow  it 
>> would be if used sparingly at the author's discretion.
> 


Received on Wednesday, 23 July 2008 21:25:11 GMT

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