The negation pseudo-class, :not(), is a functional pseudo-class taking a selector list as an argument.

A list of simple/compound/complex selectors is a comma-separated list of simple, compound, or complex selectors. This is also called just a selector list when the type is either unimportant or specified in the surrounding prose; if the type is important and unspecified, it defaults to meaning a list of complex selectors.

A complex selector is a sequence of one or more compound selectors separated by combinators.

A compound selector is a sequence of simple selectors that are not separated by a combinator

A simple selector is a single condition on an element. A type selector, universal selector, attribute selector, class selector, ID selector, or pseudo-class is a simple selector.

1 and 1px do not match the grammars for type selectors, universal selectors, attribute selectors, class selectors, ID selectors, or pseudo-classes. Therefore they are not valid simple selectors, therefore not valid compound selectors, therefore not valid complex selectors, therefore not a valid selector list, therefore not a valid argument to :not(), therefore it is a parsing error in that selector (being a token which is not allowed at that parsing point) and :not() is invalid and any selector containing it is also invalid.

[selectors] Error handling is not exhaustive? #2352

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions