- From: Paul Arzul <paul.arzul@gmail.com>
- Date: Mon, 10 Nov 2008 08:53:31 +0200
(whatwg, please see last bit.) 2008/11/9 Jukka K. Korpela <jkorpela at cs.tut.fi>: > Benjamin Hawkes-Lewis wrote: > >> Paul Arzul wrote: >>> >>> CSS defines when properties are applicable (see the Applies column: >>> <http://www.w3.org/TR/CSS21/propidx.html>) >>> >>> Should we generate warnings when properties are not applicable? For >>> example: p >>> { >>> border-collapse : collapse; >>> } >>> >>> We could warn about the paragraph not being a table or inline-table >>> element. (I get no warnings with Warnings set to All.) >> >> That would only be reliable if one could assume default CSS for HTML >> and that p was an HTML element rather than an element in some random >> XML dialect - but you can't assume either from the raw CSS. i thought you could with css namespaces: http://www.w3.org/TR/css3-namespace/ please don't loose sight of the most common use case - an html file with some css. are the css validator's web logs public? what do they have to say? i'd love to know: * how much css is validated off non-xhtml xml and how much is (x)html? * how much traction css namespaces are getting > Even in that case, the assumptions might fail because the document has > intentionally been written or styled against your expectations. i wasn't making assumptions. i was expecting the validator to check against a running total (computed) value and not a static list which is but a starting point for default values. > But you _could_ issue warnings that are solely based on applicability > statements made within CSS specs. For example, you could check whether the > display property has the value table and if not, issue a non-applicability > warning about border-collapse. Of course this means that you would need to > include some assumed default browser style sheet, so that you know (or think > you know) the default values for the display property of different elements, > for example. we could use the "Default style sheet for HTML 4": http://www.w3.org/TR/CSS21/sample.html some research against common browsers's user agent stylesheets should be done to check for any serious discrepancies. > Besides, you cannot really know the properties of an element by analyzing > one style sheet only, even if you assume that the document is HTML. Any > other style sheet (that will be used when rendering the document, along with > the style sheet being analyzed) might assign display: table, making > border-collapse applicable. (i suggested a warning, not an error.) as always the cascade applies, but it is still useful to know that a single css file is generating warnings since someone else might decide to include it without following your imports. we could also recommend validating from the root/base html or css due to cascade implications. >> The validator could include additional UI (e.g. checkboxes to indicate >> that this CSS if for HTML and the valiator should assume the suggested >> default CSS from CSS 2.1) that would mitigate those problems. > > I have no specific objections, but who is going to define what is and what > is not applicable to different elements then? is it unfortunate that the html4 stylesheet is only informative? perhaps html5 could then consider giving us a normative default user agent stylesheet - or at least a normative version with only display properties. - p
Received on Sunday, 9 November 2008 22:53:31 UTC