- From: Boris Zbarsky <bzbarsky@MIT.EDU>
- Date: Thu, 11 Feb 2010 12:26:23 -0500
- To: Anne van Kesteren <annevk@opera.com>
- CC: CSS WG <www-style@w3.org>
On 2/11/10 12:14 PM, Anne van Kesteren wrote: >> For what it's worth, the Gecko behavior for "overflow" is to return a >> value if the x and y values are equal and to treat it as a shorthand >> otherwise. > > For overflow-x:visible; overflow-y:auto I get auto back as resolved > value for overflow in Gecko. Yes, because http://www.w3.org/TR/css3-box/#overflow says (if you scroll down enough): The computed values of ‘overflow-x’ and ‘overflow-y’ are the same as their specified values, except that some combinations with ‘visible’ are not possible: if one is specified as ‘visible’ and the other is ‘scroll’ or ‘auto’, then ‘visible’ is set to ‘auto’. Perhaps I should have made it clearer that Gecko's decision on whether to treat as a shorthand or not depends on whether the _computed_ values of overflow-x and overflow-y are equal, not the specified values. Note that this same draft has this verbiage: The computed value of ‘overflow’ is equal to the computed value of ‘overflow-x’ if ‘overflow-y’ is the same; otherwise it is the pair of computed values of ‘overflow-x’ and ‘overflow-y’. So maybe that's the answer: have all newly shorthanded things specify what their computed value is. Or something. > What we could do is return values for all shorthand properties unless > the individual properties make that impossible. E.g. border-color with > four different colors does not fit in border. However this has the > potential for breaking pages as well if they expect the empty string for > some reason. It could also be a bit of a pain to implement, and worse yet can cause behavior to change on existing pages for cases when subproperties are specified and then the computed shorthand value is queried if the shorthand starts setting more properties than before... -Boris
Received on Thursday, 11 February 2010 17:26:59 UTC