ServiceWorkerContainer: controller property
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Web Workers.
The controller read-only property of the ServiceWorkerContainer interface represents the active service worker controlling the current page (associated with this ServiceWorkerContainer), or null if the page has no active or activating service worker.
This is the same object returned by ServiceWorkerRegistration.active.
Value
A ServiceWorker object if its state is activating or activated, or null if there is no active worker.
The property also returns null if the request is a force refresh (Shift + refresh)
Examples
Test if a page is controlled by a service worker
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
| Specification |
|---|
| Service Workers # navigator-service-worker-controller |