[csswg-drafts] [css-shadow-parts] make clear that Shadow Parts for built-in elements should not be supported without standardization (#3674)

heycam has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-shadow-parts] make clear that Shadow Parts for built-in elements should not be supported without standardization ==
https://drafts.csswg.org/css-shadow-parts/

The `::part()` pseudo-element looks to be a natural syntax to use to expose access to bits of built-in HTML form controls, such as the button in an `<input type=file>`.  We at Mozilla have a concern that this syntax will be used to expose parts of built-in elements (i.e. not custom element defined elements) without going through the standardization process.  We have seen in the past that engines have readily exposed `::-webkit-*` and `::-moz-*` pseudo elements so that authors can style bits of built-in elements.  Solving the HTML form element stylability problem is a big task, and we would like to avoid vendors exposing their built-in element internals through `::part()` without discussion in an appropriate standards group.  We request that a note be added to the spec clarifying that `::part()` is not to be used as a general implementation defined extension mechanism, and that any exposure of built-in element parts should be done by going through the regular standardization process.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3674 using your GitHub account

Received on Sunday, 24 February 2019 04:35:24 UTC