Web/API/EventSource/EventSource

The EventSource() constructor returns a newly-created EventSource, which represents a remote resource.

Syntax

eventSource = new EventSource(url, configuration);

Parameters

url

A USVString that represents the location of the remote resource serving the events/messages.

configuration Optional

Provides options to configure the new connection. The possible entries are:

• withCredentials, defaulting to false, indicating if CORS should be set to include credentials.

Examples

var evtSource = new EventSource('sse.php');
var eventList = document.querySelector('ul');

evtSource.onmessage = function(e) {
  var newElement = document.createElement("li");

  newElement.textContent = "message: " + e.data;
  eventList.appendChild(newElement);
}

Note: You can find a full example on GitHub — see Simple SSE demo using PHP.

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'EventSource()' in that specification.	Living Standard	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	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
EventSource() constructor	Chrome Full support 9	Edge Full support 79	Firefox Full support 6	IE No support No	Opera Full support 11	Safari Full support 5	WebView Android Full support Yes	Chrome Android Full support 18	Firefox Android Full support 45	Opera Android Full support 12	Safari iOS Full support 5	Samsung Internet Android Full support 1.0
CORS support (withCredentials)	Chrome Full support 26	Edge Full support 79	Firefox Full support 11	IE No support No	Opera Full support 12	Safari ?	WebView Android Full support Yes	Chrome Android Full support 26	Firefox Android Full support 45	Opera Android Full support 12	Safari iOS ?	Samsung Internet Android Full support 2.0

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

See also

• EventSource

EventSource() by Mozilla Contributors is licensed under CC-BY-SA 2.5.