ExtendableMessageEvent.lastEventId
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 ExtendableMessageEvent
interface represents, in server-sent events, the last event ID of the event source.
Syntax
var myLastEventId = ExtendableMessageEventInstance.lastEventId;
Value
A DOMString
.
Examples
When the following code is used inside a service worker to respond to a push messages by sending the data received via PushMessageData
to the main context via a channel message, the event object of onmessage
will be a ExtendableMessageEvent
.
var port; self.addEventListener('push', function(e) { var obj = e.data.json(); if(obj.action === 'subscribe' || obj.action === 'unsubscribe') { port.postMessage(obj); } else if(obj.action === 'init' || obj.action === 'chatMsg') { port.postMessage(obj); } }); self.onmessage = function(e) { console.log(e.lastEventId); port = e.ports[0]; }
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'ExtendableMessageEvent.lastEventId' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | ? | 45.0 (45.0)[1] | 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 | No support | (Yes) | (Yes) | No support | ? | No support | ? |
[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/extendablemessageevent/lasteventid