ServiceWorkerContainer: controller property

{{APIRef("Service Workers API")}} {{SecureContext_Header}} {{AvailableInWorkers}} 

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

Value

A {{domxref("ServiceWorker")}}  object.

Examples

if ("serviceWorker" in navigator) {
  // Do a one-off check to see if a service worker's in control.
  if (navigator.serviceWorker.controller) {
    console.log(
      `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.");
}

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}}