The startMessages()
method of the ServiceWorkerContainer
interface explicitly starts the flow of messages being dispatched from a service worker to pages under its control (e.g. sent via Client.postMessage()
). This can be used to react to sent messages earlier, even before that page's content has finished loading.
Explanation
By default, all messages sent from a page's controlling service worker to the page (using Client.postMessage()
) are queued while the page is loading, and get dispatched once the page's HTML document has been loaded and parsed (i.e. after the DOMContentLoaded
event fires). It's possible to start dispatching these messages earlier by calling ServiceWorkerContainer.startMessages()
, for example if you've invoked a message handler using EventTarget.addEventListener()
before the page has finished loading, but want to start processing the messages right away.
Note: The messages start being sent automatically when setting the handler directly using ServiceWorkerContainer.onmessage
. In this you don't need startMessages()
.
Syntax
serviceWorkerContainer.startMessages();
Parameters
None.
Return value
undefined
.
Examples
if('serviceWorker' in navigator) { navigator.serviceWorker .register('/sw.js') .then(function() { console.log('Service Worker Registered'); }); } // ... navigator.serviceWorker.addEventListener('message', (e) => { // ... }); navigator.serviceWorker.startMessages();
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'ServiceWorkerContainer: startMessages()' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
startMessages | Chrome Full support 74 | Edge Full support ≤79 | Firefox Full support 64 | IE No support No | Opera Full support 62 | Safari Full support Yes | WebView Android Full support 74 | Chrome Android Full support 74 | Firefox Android Full support 64 | Opera Android Full support 50 | Safari iOS Full support Yes | Samsung Internet Android Full support 11.0 |
Legend
- Full support
- Full support
- No support
- No support