Release
Scoped custom element registries end tag clashes
DEV · By richi.codes ·
The Brief
- Scoped custom element registries let two libraries define the same custom element name on one page without breaking each other.
- The feature became Baseline on 27 October 2026, when Firefox 159 shipped it.
- Chrome and Edge 146 are also named in the source as supporting the feature.
Why it matters
Developers combining several component libraries on one page can avoid tag name collisions that previously broke one of them.
Who’s affected
- Web component library authors
- Teams combining multiple component libraries on one page
- Firefox 159
- Chrome 146
- Edge 146
- #web components
- #custom elements
- #browsers
- #baseline
- #javascript
This note has an interactive demo. Try it in the original Two libraries can now define the same custom element name on one page without breaking each other. Scoped custom element registries became Baseline on 27 October 2026, when Firefox 159 shipped them. Chrome and Edge 146 and…
Timeline
Scoped custom element registries became Baseline when Firefox 159 shipped them
DEV Community: javascript
Scoped custom element registries end tag clashes