W3C home > Mailing lists > Public > www-style@w3.org > October 2012

[cssom] Proposing a getDefaultComputedStyle method

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Fri, 12 Oct 2012 14:36:33 -0400
Message-ID: <50786331.6080905@mit.edu>
To: www-style list <www-style@w3.org>
Proposal: a getDefaultComputedStyle method that acts just like 
getComputedStyle but returns what the style would be if it were not for 
author rules.

Rationale: jQuery has hacks to try to figure out default styles, 
involving creation of subframes and so forth.  These hacks are very 
fragile.  There's got to be a better way for libraries to do this sort 
of thing.

IDL:

     CSSStyleDeclaration
       getDefaultComputedStyle(Element elt,
                               optional DOMString pseudoElt);

Behavior is just like getComputedStyle except:

1) Ignores all author-level sheets, transitions, animations,
    override stylesheets.
2) Never returns used styles, only computed ones (just like
    getComputedStyle would for a display:none element).

My implementation at the moment also ignores presentational hints, but 
I'm open to changing that if people think it would be better to include 
them.

See also https://bugzilla.mozilla.org/show_bug.cgi?id=800983 for the 
implementation and https://bugzilla.mozilla.org/show_bug.cgi?id=797029 
for the jQuery issues that prompted this suggestion.  The jQuery folks 
sound like they would really like something like this, for what it's worth.

-Boris
Received on Friday, 12 October 2012 18:37:02 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 17:21:01 GMT