[csswg-drafts] [selectors-4] Clarify the value range of pseudo selectors (#11299)

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

== [selectors-4] Clarify the value range of pseudo selectors ==
[§ Grammar](https://drafts.csswg.org/selectors-4/#grammar) defines pseudos with a relatively open range of values that does not come with any restriction, at least not within reasonable reading proximity.

[§ Pseudo-elements](https://drafts.csswg.org/selectors-4/#pseudo-elements) says that pseudos are defined by CSS specifications **and** the host language.

[§ Invalid Selectors](https://drafts.csswg.org/selectors-4/#invalid) says that *UAs must treat as invalid any pseudos for which they have no usable level of support*. But in a non-normative note, as reported in #8305. [§ Appendix B: [...] Web Compat](https://drafts.csswg.org/selectors-4/#compat) adds an exception: UAs must support `::webkit-unknown` even if they have no support for it.

A note similar to the one below could be added in § Grammar:

  > The `<pseudo-element-selector>` and `<pseudo-class-selector>` productions are intentionally open to represent any pseudo-class and pseudo-element defined in CSS specifications or by the host language, that is supported by the UA. As per [Patial implementations](https://drafts.csswg.org/selectors-4/#w3c-partial), other pseudos are otherwise invalid, unless otherwise specified (like in [§ Appendix B: [...] Web Compat](https://drafts.csswg.org/selectors-4/#compat)).

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/11299 using your GitHub account


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Received on Saturday, 30 November 2024 13:10:56 UTC