WPT
wpt / custom-elements / HTMLElement-attachInternals.html
Spec: https://html.spec.whatwg.org/multipage/custom-elements.html ↗
Runs: Chrome 155.0.8039.0 (wpt@752608e1a, 2026-09-03) | Firefox 157.0a1 (wpt@752608e1a, 2026-09-03) | Safari 251 preview (wpt@5ce815a83, 2026-08-27) | Ladybird 1.0-a9df8 (wpt@9b4cabf6d, 2026-09-03) | Servo Servo 0.6 (wpt@7e3d005d7, 2026-09-03) | Blitz a50cb8971 (wpt@a95401e4e, 2026-09-03)
View on the Blitz WPT dashboard | Open test on wpt.live | wpt.fyi
| Chrome | Firefox | Safari | Ladybird | Servo | Blitz | |
|---|---|---|---|---|---|---|
| Total | 4/4 | 4/4 | 4/4 | 4/4 | 4/4 | NOT RUN |
| Subtest | Chrome | Firefox | Safari | Ladybird | Servo | Blitz |
|---|---|---|---|---|---|---|
| Successful attachInternals() and the second call. | PASS | PASS | PASS | PASS | PASS | — |
| attachInternals() throws a NotSupportedError if it is called for a customized built-in element | PASS | PASS | PASS | PASS | PASS | — |
| If a custom element definition for the local name of the element doesn't exist, throw an NotSupportedError | PASS | PASS | PASS | PASS | PASS | — |
| If a custom element definition for the local name of the element has disable internals flag, throw a NotSupportedError | PASS | PASS | PASS | PASS | PASS | — |