Window: customElements property

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

ThecustomElements read-only property of theWindow interface returns a reference to theCustomElementRegistry object, which can be used to register newcustom elements and get information about previously registered custom elements.

Examples

The most common example you'll see of this property being used is to get access to theCustomElementRegistry.define() method to define and register a new custom element, e.g.:

let customElementRegistry = window.customElements;customElementRegistry.define("my-custom-element", MyCustomElement);

However, it is usually shortened to something like the following:

customElements.define(  "element-details",  class extends HTMLElement {    constructor() {      super();      const template = document.getElementById(        "element-details-template",      ).content;      const shadowRoot = this.attachShadow({ mode: "open" }).appendChild(        template.cloneNode(true),      );    }  },);

See ourweb-components-examples repo for more usage examples.