Service Worker Sample: Immediate Control

Available in Chrome 42+

This sample is a modified version of the detailed registration sample. It shows off two new methods available to service workers:

• skipWaiting(): During a service worker update, when there's an existing service worker that differs from the updated service worker, the updated service worker is immediately considered active, instead of waiting.
• clients.claim(): Causes the activated service worker to take control over all open pages under the scope immediately, rather than taking control only after the next navigation.

While both of those methods have independent uses, when used together they ensure that when there's an update to the underlying service worker, the update takes effect immediately and applies to both the current page and all other active pages. It's important that your new service worker code behaves properly when assuming control of a page that might have been initially loaded with an older version of your service worker and older cache entries. If you're not sure that it will, then relying on the default service lifecycle behavior may be more appropriate.

Various pieces of information about the service worker from the perspective of the registering page can be found below. Additionally, visit chrome://inspect/#service-workers and click on the "inspect" link below the registered service worker to view logging statements for the various actions the service-worker.js script is performing.