[whatwg] [CSSWG][selectors-4] Updated WD of Selectors L4

fantasai fantasai.lists at inkedblade.net
Wed Nov 21 12:03:22 PST 2018

The CSS WG has published an updated Working Draft of Selectors Level 4:


Selectors are patterns that match against elements in a tree and are used
as a core part of CSS and in DOM methods such as .querySelector()

This update adds, drops, and renames a number of selectors:
   * zero-specificity pseudo-class named :where()
   * :matches() renamed to :is()
   * :blank defined to select empty user input elements
   * :empty redefined to ignore whitespace-only text nodes
   * :drop() dropped due to removal of support in HTML
   * Added case-sensitive attribute value matching flag

In addition, the specificity rules for :is() and :nth-child() were altered
to use the most specific selector argument rather than the most specific
selector that happened to match. See
and discussion in

Changes since the February 2018 WD are all listed at:

One major issue that's open is redefining the way invalid selectors are
handled within `:is()` and similar pseudo-classes to ignore unknown
selectors rather than invalidating the entire style rule. See

Another series of open issues concerns the :visited pseudo-class and
how to balance security concerns with usability requirements. See e.g.

Please review the draft, and send any comments to the CSSWG mailing list,
<www-style at w3.org>, prefixed with [selectors-4] (as I did on this
message) or (preferably) file them in the GitHub repository at

For the CSS WG,

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