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[cssom][css-cascade] Access to specified or cascaded values in OM?

From: L. David Baron <dbaron@dbaron.org>
Date: Mon, 24 Jun 2013 15:30:04 -0700
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: www-style list <www-style@w3.org>
Message-ID: <20130624223004.GA20165@crum.dbaron.org>
On Monday 2013-06-24 14:16 -0700, Tab Atkins Jr. wrote:
> The term "specified value" has always been confusing, because it does
> *not* refer to the value the author specified.  Instead, it's always
> referred to the value that starts the standard value-computation
> chain, at the point where a given element has a value for every
> property.
> 
> Ironically, we don't actually *have* a term for the value the author
> actually specified in the stylesheet, or the close-enough concept of
> what CSSStyleDeclaration returns.
> 
> Private conversation with dbaron (in #css) led to the following suggestions:
> 
> 1. Use "declared value" for the value of a declaration; that is, what
> is returned when you query CSSStyleDeclaration.  This is not
> associated with any particular element, and may not have a value for
> every property.
> 
> 2. Drop the term "specified value", and slightly modify Cascade so
> that "cascaded value" fills the role.  This just requires us to
> slightly change the verbiage around how we handle the global keywords;
> currently, the "cascaded value" may be empty or resolve to one of the
> global keywords.  We'd change it so that as part of the computation of
> the cascaded value, we guarantee that we fill in a value, and resolve
> away the global keywords.  (Our current use of "cascaded value" in the
> spec is unobservable from the outside, and we can just lean on the
> term "result of the cascade" to represent the value that might be
> empty or might be a global keyword.)

One further issue is what
http://dev.w3.org/csswg/cssom/#getstyleutils should specify access
to.

Do authors want access to cascaded values (sometimes empty, and with
'initial' and 'inherit' as they are) or specified values (with
'initial' and 'inherit' resolved and any empty values replaced with
the inherited or initial value)?  I don't recall the use cases here
to recall which is useful (one, both, or neither).

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂
Received on Monday, 24 June 2013 22:30:42 UTC

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