Limited Availability Custom elements

Scoped custom element registries

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.

Baseline Status: This feature is currently Limited (not yet Baseline). Latest engine implementation shipped on Mar 13, 2026.

Desktop Browser Engine Support

Google Chrome

146

Supported

Mozilla Firefox

—

Unsupported

Apple Safari

26

Supported

Microsoft Edge

146

Supported

Mobile Browser Engine Support

Chrome Android

146

Firefox Android

—

Safari iOS

26

Specifications and References

Specification ↗ Specification ↗ Feature XML ↗

MDN Browser Compat Data Keys:

api.CustomElementRegistry.CustomElementRegistry ↗ api.CustomElementRegistry.initialize ↗ api.Document.customElementRegistry ↗ api.Element.customElementRegistry ↗ api.HTMLTemplateElement.shadowRootCustomElementRegistry ↗ api.ShadowRoot.customElementRegistry ↗