:is() pseudo-class has been unprefixed


Categories: CSS

Releases: Firefox 78, Firefox 78 ESR


The :is() and :where() CSS pseudo-classes from the Selectors Level 4 spec have been enabled with Firefox 78. In Firefox, :is() had been implemented as :-moz-any() for a long time. The prefixed pseudo-class is still available but may be removed in the future. Make sure to use both the standard and non-standard versions to future-proof your website.

How can I test this?

This change can be tested with the compatibilty checker in our Firefox Developer Tools extension. Get it today!