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 an item to the CustomStateSet, after checking that the value is in the correct format.

Syntax

js

add(value)

Parameters

value

A string which must be a <dashed-ident>, with the form --mystate.

Return value

Undefined.

Exceptions

SyntaxError DOMException

Thrown if the string is not a <dashed-ident>.

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
Custom State Pseudo Class
# dom-customstateset-add

Browser compatibility

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