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Re: [css3-selectors] Implementing jQuery E: has(F) selector

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Fri, 10 Jul 2009 09:56:11 -0700
Message-ID: <4A5772AB.1090303@mit.edu>
To: Gabriele Romanato <gabriele.romanato@gmail.com>
CC: www-style@w3.org
Gabriele Romanato wrote:
> Dear all,
> the E:has(F) selector matches an E element when it has a F element 
> within it. I think that's a powerful feature that should be implemented.

I suggest looking at the archives; this has been brought up before.

> I don't think it's very difficult to implement, because if it's true 
> that it's been implemented in JavaScript, it's also true that it would 
> be very easy
> to implement in a more powerful programming language, such as C++

There are several logical fallacies here (ranging from the fact that JS 
is in fact a higher-level language than C++, hence "more powerful" for 
most reasonably meanings of the term) to the assumption that the jquery 
implementation is a reasonable example of what a browser would need to 
implement (it's not; it works on a static DOM snapshot and doesn't have 
to deal with dynamic changes).

> ps. if you think, as implementor, that it's still too "expensive", well, 
> I don't see the point if you think in terms of incremental 
> rendering and reflow model
> (see http://mxr.mozilla.org/firefox/search?string=reflow for a redundant 
> overview. HTML docs there are obsolete (NGLayout is from 1998!).

I have no idea what you're talking about here.

If you think this is really easy to implement, though, we (Mozilla) are 
always accepting patches.  I hear so is Webkit.  I would be happy to 
shepherd any patch you create for this "not very difficult to implement" 
feature into the tree, assuming it doesn't have any undesirable 
performance impact.

Received on Friday, 10 July 2009 16:56:56 UTC

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