WPT
wpt / custom-elements / custom-element-reaction-queue.html
Spec: https://html.spec.whatwg.org/multipage/custom-elements.html ↗
Runs: Chrome 155.0.8042.0 (wpt@0a3996025, 2026-09-04) | Firefox 157.0a1 (wpt@972e0e100, 2026-09-04) | Safari 251 preview (wpt@972e0e100, 2026-09-04) | Ladybird 1.0-481bc (wpt@d317428a6, 2026-09-05) | Servo Servo 0.6 (wpt@2c385f65e, 2026-09-04) | 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 | 6/6 | 6/6 | 6/6 | 5/6 | 6/6 | NOT RUN |
| Subtest | Chrome | Firefox | Safari | Ladybird | Servo | Blitz |
|---|---|---|---|---|---|---|
| Upgrading a custom element must invoke attributeChangedCallback and connectedCallback before start upgrading another element | PASS | PASS | PASS | PASS | PASS | — |
| Upgrading a custom element must not invoke attributeChangedCallback for the attribute that is changed during upgrading | PASS | PASS | PASS | PASS | PASS | — |
| Upgrading a custom element must not invoke disconnectedCallback if the element is disconnected during upgrading | PASS | PASS | PASS | PASS | PASS | — |
| Upgrading a disconnected custom element must not invoke connectedCallback if the element is connected during upgrading | PASS | PASS | PASS | PASS | PASS | — |
| Mutating a undefined custom element while upgrading a custom element must not enqueue or invoke reactions on the mutated element | PASS | PASS | PASS | PASS | PASS | — |
| Mutating another custom element inside adopted callback must invoke all pending callbacks on the mutated element | PASS | PASS | PASS | FAIL | PASS | — |