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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
EventSource() constructorChrome Full support 9Edge Full support 79Firefox Full support 6IE No support NoOpera Full support 11Safari Full support 5WebView Android Full support YesChrome Android Full support 18Firefox Android Full support 45Opera Android Full support 12Safari iOS Full support 5Samsung Internet Android Full support 1.0
CORS support (withCredentials)Chrome Full support 26Edge Full support 79Firefox Full support 11IE No support NoOpera Full support 12Safari ? WebView Android Full support YesChrome Android Full support 26Firefox Android Full support 45Opera Android Full support 12Safari iOS ? Samsung Internet Android Full support 2.0

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown

See also