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This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The :where() CSS pseudo-class function takes a selector list as its argument, and selects any element that can be selected by one of the selectors in that list.

The difference between :where() and :is() is that :where() always has 0 specificity, whereas :is() takes on the specificity of the most specific selector in its arguments.

Syntax

:where( <complex-selector-list> )

where
<complex-selector-list> = <complex-selector>#

where
<complex-selector> = <compound-selector> [ <combinator>? <compound-selector> ]*

where
<compound-selector> = [ <type-selector>? <subclass-selector>* [ <pseudo-element-selector> <pseudo-class-selector>* ]* ]!
<combinator> = '>' | '+' | '~' | [ '||' ]

where
<type-selector> = <wq-name> | <ns-prefix>? '*'
<subclass-selector> = <id-selector> | <class-selector> | <attribute-selector> | <pseudo-class-selector>
<pseudo-element-selector> = ':' <pseudo-class-selector>
<pseudo-class-selector> = ':' <ident-token> | ':' <function-token> <any-value> ')'

where
<wq-name> = <ns-prefix>? <ident-token>
<ns-prefix> = [ <ident-token> | '*' ]? |
<id-selector> = <hash-token>
<class-selector> = '.' <ident-token>
<attribute-selector> = '[' <wq-name> ']' | '[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'

where
<attr-matcher> = [ '~' | | | '^' | '$' | '*' ]? '='
<attr-modifier> = i | s

Specifications

Specification Status Comment
Selectors Level 4
The definition of ':where()' in that specification.
Working Draft Initial definition.

Browser compatibility

No compatibility data found. Please contribute data for "css.selectors.where" (depth: 1) to the MDN compatibility data repository.

See also

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