[webkit-dev] (no subject)

Brendan Eich brendan at mozilla.org
Sun Apr 29 15:30:39 PDT 2012

Maciej Stachowiak wrote:
> On Apr 29, 2012, at 1:25 PM, Ryosuke Niwa<rniwa at webkit.org>  wrote:
>> I'm actually curious as to how the session participants reached this consensus (probably on a separate thread). It seems like the bar shouldn't too high for removing prefixed APIs when they are unprefixed equivalents because I'm certain web developers want to use the ones that work on all browsers instead of just on WebKit.
> Here's some evidence that Web developers do not always care about this, and that lack of support for webkit-prefixed properties can be detrimental to Web compatibility:
> http://dev.opera.com/articles/view/opera-mobile-emulator-experimental-webkit-prefix-support/

I agree with this, including the careful "do not always" and "can be 
detrimental" words ;-).

This message may not be interesting to webkit-dev. Skip if you are not 
interested in prefix usage studies, what Mozilla might do about 
prefixes, etc.

We have been studying prefix usage in:


The situation for Opera is much worse than for Mozilla for many 
properties, e.g. border-radius, where -moz- is often observed to be used 
alongside -webkit-.

See in particular:


The table's tabs don't lay out nicely in bugzilla. Here's my attempt at 
fixing the layout by hand:

base_property              num_domains  num_rules  
animation-count            1            1          100.0
animation-delay            5            137         80.0
animation-direction        8            10          62.5
animation-duration         73           324         87.9
animation-fill-mode        2            3           50.0
animation-iteration-count  51           78          84.7
animation-name             72           756         87.6
animation-play-state       2            3            0.0
animation-timing-function  51           100         94.5
text-size-adjust           779          6352        99.5
transform-origin           68           196         56.9
transform-origin-y         2            3            0.0
transform-style            35           50         100.0
transition-delay           19           53          63.2
transition-duration        208          853         71.5
transition-property        156          491         76.2
transition-timing          1            2            0.0
transition-timing-function 45           111         58.9

Clearly Mozilla feels Opera's pain for certain properties, e.g. 
text-size-adjust. Per the bug, 99.5% of 6352 found instances do not have 
unprefixed or -moz-prefixed equivalents of text-size-adjust.

Lack of -webkit- prefix support may not be detrimental to a particular 
browser's mobile web compatibility where that browser engine's prefix 
(or no prefix) is widely used. It depends on the browser and the 
particular style property.

So (just FYI) we at Mozilla are not contemplating emulating -webkit- 
quite so much as Opera may be. We do want to sort this all out in the 
CSS-WG and avoid unnecessary fragmentation.


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