[webkit-dev] AX: Implement CSS -webkit-alt property (text alternative for generated content pseudo-elements ::before and ::after)

Dean Jackson dino at apple.com
Fri Oct 4 13:37:47 PDT 2013

On 5 Oct 2013, at 6:22 am, Adam Barth <abarth at webkit.org> wrote:

> On Fri, Oct 4, 2013 at 12:08 PM, Dean Jackson <dino at apple.com> wrote:
>> On 3 Oct 2013, at 4:46 am, Christian Biesinger <cbiesinger at chromium.org> wrote:
>>> On Tue, Oct 1, 2013 at 8:26 PM, Ryosuke Niwa <rniwa at webkit.org> wrote:
>>>> On Tue, Oct 1, 2013 at 4:53 PM, James Craig <jcraig at apple.com> wrote:
>>>>> Follow-up question:  Since this hasn’t made it into the CSS4 spec yet,
>>>>> should we temporarily use “-webkit-alt” for the property name? I know there
>>>>> has been a push to move away from vendor prefixes lately, so if there are no
>>>>> objections, I propose we use the unprefixed version.
>>>> I think that's what Mozilla and Google are doing but I don't think we
>>>> necessary have to follow the suit.
>>> FYI, because IMO this is an important clarification - Mozilla and
>>> Google use unprefixed versions only *behind a (runtime) flag*, until
>>> the spec is stable. That way experimental features are not exposed to
>>> the web at large until it is unlikely that the spec will change, to
>>> avoid cross-browser compatibility risks.
>> We decided on a slightly different approach, which is to prefix things
>> but enable them by default in nightly builds. That way a port must still
>> decide at their shipping time whether or not to enable the feature.
>> In the Moz + Google case, the experimental form is exposed unprefixed to a small
>> number of users on the Web. In our case, the experimental form is exposed
>> prefixed. We concluded that we’ve changed things enough times while prefixed
>> that it was worth the extra “this is experimental and may change” notice.
> Does this imply that you'll remove the prefixes before shipping the
> features in a production release?

I can’t speak for anyone other than the Apple port, and even there I’m
definitely not the official word on the topic, but I don’t think that is
implied. It’s likely going to depend on perceived stability of the feature,
testing, community feedback, etc.

The important thing is that our goal is to get to the unprefixed stable form
as soon as possible.

Also, our prefixing/unprefixing rules are not set in stone. I think the community
will evaluate them case by case.


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