Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The serviceWorker read-only property of the Navigator interface returns the ServiceWorkerContainer object for the associated document, which provides access to registration, removal, upgrade, and communication with the ServiceWorker.
The feature may not be available in private mode.
Note that a worker can similarly access the ServiceWorkerContainer for a document using WorkerNavigator.serviceWorker.
This code checks if the browser supports service workers.
if ("serviceWorker" in navigator) {
// Supported!
}