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EventSource()

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

Syntax

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
HTML Standard # dom-eventsource-dev

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`EventSource`	6	79	6	No	11	5	4.4	18	45	12	5	1.0
`cors_support`	26	79	11	No	12	7	≤37	26	45	12	7	2.0