Scoped custom element registriesLimited availability

The CustomElementRegistry() constructor creates a new custom element registry that's separate from the global window.customElements registry. Creating more than one registry is useful for multiple custom elements that have the same tag name to coexist.

Not yet supported in all major browsers — check the table and provide a fallback.

How to use ↓Compare browsers

Browser support

DesktopChrome

1–145Not supported

146+Supportedsince Mar 10, 2026

Current: 155

Edge

12–145Not supported

146+Supportedsince Mar 13, 2026

Current: 154

Firefox

✕Not supportedup to 157

Current: 157

Safari

1–18.6Not supported

26+Supportedsince Sep 15, 2025

Current: 27

MobileChrome Android

18–145Not supported

146+Supportedsince Mar 10, 2026

Current: 155

Firefox Android

✕Not supportedup to 157

Current: 157

Safari iOS

1–18.6Not supported

26+Supportedsince Sep 15, 2025

Current: 27

How to use

Not supported in Firefox, Firefox Android. Use feature detection below and provide a fallback (or a polyfill) for those browsers.

Example

Full syntax and examples are on MDN: CustomElementRegistry.

Feature detection

JS · check before using

if ("CustomElementRegistry" in globalThis && "CustomElementRegistry" in CustomElementRegistry.prototype) {
  // CustomElementRegistry.CustomElementRegistry is available
}

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (6). The overall table above shows when the whole feature works.

Sub-feature	Chrome	Edge	Firefox	Safari	Chrome Android	Firefox Android	Safari iOS
CustomElementRegistry.CustomElementRegistry	146	146	✕	26	146	✕	26
CustomElementRegistry.initialize	146	146	✕	26	146	✕	26
Document.customElementRegistry	146	146	✕	26	146	✕	26
Element.customElementRegistry	146	146	✕	26	146	✕	26
HTMLTemplateElement.shadowRootCustomElementRegistry	146	146	✕	26	146	✕	26
ShadowRoot.customElementRegistry	146	146	✕	26	146	✕	26