The :required CSS pseudo-class represents any <input> element that has the required attribute set on it. This allows forms to easily indicate which fields must have valid data before the form can be submitted.

The :optional pseudo-class may be used to provide an appearance for optional form fields.


See :invalid for an example.


Specification Status Comment
WHATWG HTML Living Standard
The definition of ':required' in that specification.
Living Standard No change.
The definition of ':required' in that specification.
Recommendation Defines the semantic regarding HTML and constraint validation.
Selectors Level 4
The definition of ':required' in that specification.
Working Draft No change.
CSS Basic User Interface Module Level 3
The definition of ':required' in that specification.
Candidate Recommendation Defines the pseudo-class, but not the associated semantic.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 10.0 4.0 (2) 10 10.0 5.0
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? 4.0 (2) Not supported 10.0 5.0

See also

Document Tags and Contributors

 Contributors to this page: MusikAnimal, kscarfone, teoli, Sheppy, FredB, McGurk, nimbupani
 Last updated by: MusikAnimal,