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 lastEventID read-only property of the ServiceWorkerMessageEvent interface represents, in server-sent events, the last event ID of the event source.
Syntax
var myLastEventId = ServiceWorkerMessageEventInstance.lastEventId;
Value
A DOMString.
Examples
When the following code is used inside the main thread to set up a message channel between it and a service worker for sending messages between the two, the event object of onmessage will be a ServiceWorkerMessageEvent.
navigator.serviceWorker.ready.then(function(reg) {
...
// set up a message channel to communicate with the SW
var channel = new MessageChannel();
channel.port1.onmessage = function(e) {
console.log(e.lastEventId);
handleChannelMessage(e.data);
}
mySW = reg.active;
mySW.postMessage('hello', [channel.port2]);
});
Specifications
| Specification | Status | Comment |
|---|---|---|
| Service Workers The definition of 'ServiceWorkerMessageEvent.lastEventId' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|
| Basic support | (Yes) | 44.0 (44.0)[1] | No support | 24 | 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 | (Yes) |
[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)