An EventListener
property called whenever an event of type statechange
is fired; it is basically fired anytime the ServiceWorker.state
changes.
Syntax
ServiceWorker.onstatechange = function(statechangeevent) { ... } ServiceWorker.addEventListener('statechange', function(statechangeevent) { ... } )
Examples
This code snippet is from the service worker registration-events sample (live demo). The code listens for any change in the ServiceWorker.state
and returns its value.
var serviceWorker;
if (registration.installing) {
serviceWorker = registration.installing;
document.querySelector('#kind').textContent = 'installing';
} else if (registration.waiting) {
serviceWorker = registration.waiting;
document.querySelector('#kind').textContent = 'waiting';
} else if (registration.active) {
serviceWorker = registration.active;
document.querySelector('#kind').textContent = 'active';
}
if (serviceWorker) {
logState(serviceWorker.state);
serviceWorker.addEventListener('statechange', function(e) {
logState(e.target.state);
});
}
Note that when statechange
fires, the service worker's references may have changed. For example:
navigator.serviceWorker.register(..).then(function(swr) {
swr.installing.state == "installing"
swr.installing.onstatechange = function() {
swr.installing == null;
// At this point, swr.waiting OR swr.active might be true. This is because the statechange
// event gets queued, meanwhile the underlying worker may have gone into the waiting
// state and will be immediately activated if possible.
}
})
Specifications
Specification | Status | Comment |
Service WorkersThe definition of 'ServiceWorker.onstatechange' in that specification. | Working Draft | Initial definition |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
Full support 40 |
Edge Full support 17 Full support 17 Full support 16 Disabled' From version 16: this feature is behind the |
Firefox Full support 44 Full support 44 Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API. |
IE
No support No |
Opera
Full support 27 |
Safari
Full support 11.1 |
WebView Android
Full support 40 |
Chrome Android
Full support 40 |
Firefox Android
Full support 44 |
Opera Android
Full support 27 |
Safari iOS
Full support 11.3 |
Samsung Internet Android
Full support 4.0 |
Legend
- Full support
- Full support
- No support
- No support
- Experimental. Expect behavior to change in the future.'
- Experimental. Expect behavior to change in the future.
- See implementation notes.'
- See implementation notes.
- User must explicitly enable this feature.'
- User must explicitly enable this feature.
ServiceWorker.onstatechange by Mozilla Contributors is licensed under CC-BY-SA 2.5.