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

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 9Edge No support NoFirefox Full support 6IE No support NoOpera Full support 11Safari Full support 5WebView Android Full support YesChrome Android Full support 18Edge Mobile No support NoFirefox Android Full support 6Opera Android Full support 11Safari iOS Full support 5Samsung Internet Android ?
CORS support (withCredentials)Chrome Full support 26Edge No support NoFirefox Full support 11IE No support NoOpera Full support 12Safari ? WebView Android Full support YesChrome Android Full support 26Edge Mobile No support NoFirefox Android Full support 14Opera Android Full support 12Safari iOS ? Samsung Internet Android ?

Legend

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

See also

Document Tags and Contributors

Contributors to this page: fscholz, chrisdavidmills, carlos-lopez, zemlanin, teoli
Last updated by: fscholz,