W3cubDocs

EventSource.constructor

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 Standard The definition of 'EventSource()' in that specification.	Living Standard	Initial definition

Browser compatibility

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	9	6.0 (6.0)	?	11	5
CORS support (`withCredentials`)	26	11.0 (11.0)	?	12	?
Available in shared and dedicated workers^[1]	(Yes)	53.0 (53.0)	?	(Yes)	?

Feature	Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	4.4	6.0 (6.0)	?	?	?
CORS support (`withCredentials`)	?	11.0 (11.0)	?	?	?
Available in shared and dedicated workers^[1]	?	53.0 (53.0)	?	?	?