demo · v135
srcdoc iframe is a real Service Worker client
Chrome 135 makes srcdoc documents inherit their parent page's Service Worker controller. Register the scoped worker, mount a normal same-origin iframe and an inline srcdoc iframe, then ask the worker for the measured clients.matchAll() list and broadcast a worker message into both frames.
Measured client tree
Service Worker: checking
parent controller: checking
srcdoc controller: not mounted
iframe with srcdoc=
clients.matchAll()
- Register the worker, mount frames, then ask for clients.
SW-to-frame postMessage
- No worker broadcast has run yet.
event log
the change
self.addEventListener("message", (event) => {
if (event.data.type === "list-clients") {
const clients = await self.clients.matchAll({
includeUncontrolled: true,
type: "window"
});
event.source.postMessage(clients.map((client) => ({
id: client.id,
type: client.type,
url: client.url
})));
}
});
// Before Chrome 135: srcdoc documents were skipped and the worker could not
// message them. Chrome 135+: srcdoc documents inherit the parent's controller,
// count as Service Worker clients, and receive worker postMessage events.