This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The update method of the ServiceWorkerRegistration interface attempts to update the service worker. It fetches the worker's script URL, and if the new worker is not byte-by-byte identical to the current worker, it installs the new worker. The fetch of the worker bypasses any browser caches if the previous fetch occurred over 24 hours ago.
Note: This feature is available in Web Workers.
Syntax
ServiceWorkerRegistration.update();
Parameters
None.
Returns
Void.
Example
The following simple example registers a service worker example, an then adds an event handler to a button so you can explicitly update the service worker whenever desired:
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/sw-test/sw.js', {scope: 'sw-test'}).then(function(registration) {
// registration worked
console.log('Registration succeeded.');
button.onclick = function() {
registration.update();
}
}).catch(function(error) {
// registration failed
console.log('Registration failed with ' + error);
});
};
Specifications
| Specification | Status | Comment |
|---|---|---|
| Service Workers The definition of 'ServiceWorkerRegistration.update()' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|
| Basic support | 45.0 [1] [2] | 44.0 (44.0)[3] | No support | ? | No support |
| Available in web workers | No support | 44.0 (44.0)[3] | No support | ? | No support |
| Feature | Android | Android Webview | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
|---|---|---|---|---|---|---|---|---|
| Basic support | ? | No support | 44.0 (44.0) | (Yes) | No support | ? | No support | 45.0 [1] [2] |
| Available in web workers | ? | No support | (Yes) | ? | No support | ? | No support | 45.0 [1] [2] |
- [1] Starting with Chrome 46, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception.
- [2] Before Chrome 48, this method always bypassed the browser cache. Starting with Chrome 48, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.
- [3] Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR.)