[whatwg] Quirks Mode Standard
simonp at opera.com
Thu Feb 9 23:57:43 PST 2012
On Fri, 10 Feb 2012 08:18:40 +0100, Boris Zbarsky <bzbarsky at mit.edu> wrote:
> On 2/9/12 9:51 AM, Simon Pieters wrote:
>> It is very likely that more quirks need to be added, but as I went
>> through the list I was surprised about how many of them were *not*
>> widely implemented across browsers, and so may not be needed for Web
>> compat and can be dropped.
> It's worth keeping in mind that the IE9 mode relevant for quirks "web
> compat" is the compat view quirks mode, as far as I can tell...
>> It would be useful if browser implementors could review the draft,
>> consider dropping quirks, give feedback about quirks that can't be
>> dropped, and consider aligning with other implementations for quirks
>> that are here to stay.
> 1) I'm fairly certain the "Images (img elements) without alt attributes
> sometimes display placeholder icons in quirks mode." quirk cannot be
> dropped. The real point of that quirk is that this markup:
> <img width="100" height="100" src="404.html">
> which links to some non-existent image needs to result in a box of width
> 100 and height 100 in quirks mode; not doing that breaks all the various
> pages that (still) use "spacer gifs" pointing to bogus URIs.
> I believe some UAs have this behavior in all modes; in Gecko the
> behavior is restricted to quirks mode.
The HTML specification specifies this quirk in the Rendering section.
> 2) The "fixed width specified on a table cell resets the nowrap
> attribute." quirk seems to be implemented by everyone, effectively. I
> would be really surprised if it can be dropped.
IE9 in non-compat view doesn't have it.
OK, so then either we limit this to quirks mode like Opera/Gecko or we
also do it in standards mode like WebKit/IE9 compat view.
> 3) Likewise for the "tables with no rows/rowgroups have zero height
> even when a height is specified" quirk.
> 4) The CSS parsing quirks need to define behavior for shorthands.
Other than the behavior for 'font' (assuming 'font-size' is on the list),
what's missing? (My idea was that shorthands that reference other
properties (or value productions from other properties) in their "Value:"
specification would automatically support unitless lengths, e.g.
'background' where only <position> gets rewritten to use <quirklength>
because 'background-position' is in the list but 'background-size' is not.)
> How was the list of properties for the unitless px quirk generated, by
> the way?
I went through CSS2.1's property index manually.
> It's interesting that 'font-size' is not in the list....
I trusted https://developer.mozilla.org/en/Mozilla_Quirks_Mode_Behavior
which says "The CSS parser interprets unitless numbers as px (except for
font-size because that was what Netscape Navigator 4 did...". :-) Now
added, but I'm not sure right now how to spec how the 'font' shorthand is
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