ServiceWorkerContainer: controller property

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The controller read-only property of the ServiceWorkerContainer interface returns a ServiceWorker object if its state is activating or activated (the same object returned by This property returns null if the request is a force refresh (Shift + refresh) or if there is no active worker.


A ServiceWorker object.


if ("serviceWorker" in navigator) {
  // Do a one-off check to see if a service worker's in control.
  if (navigator.serviceWorker.controller) {
      `This page is currently controlled by: ${navigator.serviceWorker.controller}`,
  } else {
    console.log("This page is not currently controlled by a service worker.");
} else {
  console.log("Service workers are not supported.");


Service Workers
# navigator-service-worker-controller

Browser compatibility

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