CustomStateSet: add() method

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

The add method of the CustomStateSet interface adds value representing a custom state to the CustomStateSet.

Custom elements with a specific state can be selected using the :state() pseudo-class, specifying the desired state as an argument.

Syntax

js
add(value)

Parameters

value

A string that represents the custom state.

Return value

Undefined.

Examples

The following function adds the state checked to a CustomStateSet.

js
class MyCustomElement extends HTMLElement {
  set checked(flag) {
    if (flag) {
      this._internals.states.add("checked");
    }
  }
}

Specifications

Specification
HTML Standard
# custom-state-pseudo-class

Browser compatibility

BCD tables only load in the browser