/Web APIs

ServiceWorkerContainer: controller property

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 ServiceWorkerRegistration.active). 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.");


Browser compatibility

Desktop Mobile
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controller 40 17 44 No 27 11.1 40 40 44 27 11.3 4.0

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