Custom pseudo-elements collisions, was: Need a better way to reach into the shadow DOM subtree


I am re-visiting this -- time to add custom pseudo-elements to Shadow
DOM spec! -- and would like to solicit ideas/opinions on the topic of
collisions. Specifically, What I am trying to avoid here is collisions
between some widget author-invented pseudo-element name with something
the CSS WG invents in a future specification.

Possible solutions:

1) Introduce a "::pseudo(name)" pseudo-element specifically for custom
pseudo-elements (Tab's idea)

2) Place a validity constraint on the pseudo-element value. For
example, it has to start with "x-".

3) your idea goes here.


On Wed, Apr 27, 2011 at 1:33 PM, Dimitri Glazkov <> wrote:
> As of, the restrictions on
> pseudo-elements are relaxed and allow chaining pseudo-elements and
> pseudo-classes at will.
> :DG<
> On Mon, Apr 11, 2011 at 12:59 PM, David Hyatt <> wrote:
>> On Apr 11, 2011, at 2:50 PM, Dimitri Glazkov wrote:
>>> video::-webkit-timeline:disabled { /* ... */ }
>>> How do we fix this? Tab suggests a new combinator selector like:
>> Just keep using pseudo-elements, but lift all the silly restrictions placed on them, e.g., that they have to be the rightmost selector.  The issue isn't with pseudo-elements.  The issue is with the restrictions placed on pseudo-element usage that don't need to be there.
>> Note that WebKit already has its own pseudo-element extensions that deliberately violate this rule, e.g., all of the scrollbar parts, which support states like hover/active/disabled using rules just like what you've described above.
>> dave
>> (

Received on Tuesday, 23 October 2012 19:59:02 UTC