abort_signal.onabort = () => onabort_called = true;
    i.remove();
  });
  await promise_rejects_dom(t, 'AbortError', iframe_constructor, i.contentWindow.navigation.navigate("#1").committed);
  assert_true(abort_signal.aborted);
  assert_true(onabort_called);
}, "window detach inside a navigate event signals event.signal");
</script>
