EventSource: open event
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.
Note: This feature is available in Web Workers.
The open
event of the EventSource
interface is fired when a connection with an event source is opened.
This event is not cancelable and does not bubble.
Syntax
Use the event name in methods like addEventListener()
, or set an event handler property.
js
addEventListener("open", (event) => {});
onopen = (event) => {};
Event type
A generic Event
.
Examples
js
const evtSource = new EventSource("sse.php");
// addEventListener version
evtSource.addEventListener("open", (e) => {
console.log("The connection has been established.");
});
// onopen version
evtSource.onopen = (e) => {
console.log("The connection has been established.");
};
Specifications
Specification |
---|
HTML Standard # event-open |
HTML Standard # handler-eventsource-onopen |
Browser compatibility
BCD tables only load in the browser