Pseudo-classes in <content> select attribute

[tomalec]

I'm trying to wrap Custom Element's child nodes (from light DOM) in its ShadowDOM.
Therefore I use pseudo-class :nth-child selector:

    <polymer-element name="my-list" noscript>
        <template>
            <ul id="container">
                <li><content select=":first-child"></content></li>
                <li><content select=":nth-child(2)"></content></li>
            </ul>
            <content></content>
        </template>
    </polymer-element>

http://jsfiddle.net/tomalec/f7bn5/3/

It works fine in stable Chrome, and Firefox, but it does not work on Canary (36.0.1932.2 enable-experimental-web-platform-features).

Am I doing it wrong, or is this a bug with Canary?

[dglazkov]

My apologies. I think this should totally work, and this is something we had implemented in Chrome, but it was taken out of the spec based on objections from other vendors: https://www.w3.org/Bugs/Public/show_bug.cgi?id=24872#c9. So we removed pseudoclass support to conform to the spec. We're going to discuss this at the W3C meeting tomorrow and see if we can bring it (or perhaps even better alternatives) back.

[tomalec]

Hi, do you have any news on this?

[mysticatea]

+1

[roberthartung]

+1 - I really would like to see this! Any news on this?

[robdodson]

Support for :not has been added
https://code.google.com/p/chromium/issues/detail?id=370670

It's a start 😸

[sorvell]

Closing since this is a spec issue. Please add feedback to the spec issue here:

https://www.w3.org/Bugs/Public/show_bug.cgi?id=24872