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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.

Value

A ServiceWorker object.

Examples

js

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

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
controller 40 17 44 No 27 11.1 40 40 44 27 11.3 4.0

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https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerContainer/controller