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Re: Margin-color; text-indent; browser detection without script; attribute selector, ! combinator

From: Matthew Brealey <thelawnet@yahoo.com>
Date: Wed, 10 Nov 1999 03:44:26 -0800 (PST)
Message-ID: <19991110114426.24732.rocketmail@web903.mail.yahoo.com>
To: www-style <www-style@w3.org>
--- "Braden N. McDaniel" <braden@endoframe.com> wrote:
> On Mon, 8 Nov 1999, Matthew Brealey wrote:
-------------------------------------------------------Attribute
> > selectors:
> > 
> > At present TABLE[border="0"] does not match
> <table>,
> > even though it actually has no border.
> > 
> > However, I would propose a refinement to the
> attribute
> > selector, where
> > TABLE[border=/"0"] matches TABLE with border
> > explicitly 0 or at its initial value.
> 
> Interesting idea, but having a selector that would
> match when a specified
> attribute is *not* set strikes me as a more flexible
> solution. Maybe
> something like
> 
>   [!att]
> 
> Thus, to replicate the effect of your example:
> 
>   table[border="0"], table[!border]

The ultimate in flexibility for ! is achieved by
making it not a combinator, but a negator.

Thus

P:!first-child = P:not-first-child

P.!x = P that is not of class x.

!(P.x) - not P class x

!(P.x) & (#!id) - not P.x and not id=id either.

So, !P means not P, BODY !> P means P that is not a
child of BODY (because the ! serves to negate that
which immediately follows it).

Equally, DIV ! H1 means not a descendant, so it
matches all P's that are not descendants of DIV.

Specificity:

I would suggest that the negator doubles the
selector's normal specificity.

Thus !(P#x) = 101 * 2 = 202.

I would be inclined to give the & combinator zero
specifity, because the fact that it will contain at
least two simple selectors gives it sufficient
specifity.
-----------
If you allow :contains as well, I think the CSS
selector syntax is given the richest possible syntax,
with the fewest possible things to remember.

Thus DIV:!(contains(P)) - DIV does not contain a P.

DIV:contains(!P) - DIV does not contain a P.

------------
The negator is definitely a huge advance on the WD,
since it contains far more selectors -
not-first-child, not-last-child, not-last-of-type,
not-first-of-type, not-only-child, not-only-of-type.
In addition, it can't do things like E !~ F


=====
----------------------------------------------------------
From Matthew Brealey (http://members.tripod.co.uk/lawnet (for law)or http://members.tripod.co.uk/lawnet/WEBFRAME.HTM (for CSS))
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Received on Wednesday, 10 November 1999 06:44:28 GMT

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