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مصدر الحدث واجهة تستخدم لإستقابال  server-sent events. It connects to a server over HTTP and receives events in text/event-stream format without closing the connection.


Creates a new EventSource from the given USVString.


This interface also inherits properties from its parent, EventTarget.

EventSource.readyState Read only
A number representing the state of the connection. Possible values are CONNECTING (0), OPEN (1), or CLOSED (2).
EventSource.url Read only
A DOMString representing the URL of the source.
EventSource.withCredentials Read only
A Boolean indicating whether the EventSource object was instantiated with CORS credentials set (true), or not (false, the default).

Event handlers

Is an EventHandler called when an error occurs and the error event is dispatched on an EventSource object.
Is an EventHandler called when a message event is received, that is when a message is coming from the source.
Is an EventHandler called when an open event is received, that is when the connection was just opened.


This interface also inherits methods from its parent, EventTarget.

Closes the connection, if any, and sets the readyState attribute to CLOSED. If the connection is already closed, the method does nothing.


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

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

  newElement.textContent = "message: " +;

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


الخصائص الحالة التعليق
HTML Living Standard
The definition of 'EventSource' in that specification.
Living Standard  

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
EventSource support 6 No support 6.0 (6.0) No support (Yes) 5
Available in shared and dedicated workers[1] (Yes) No support 53.0 (53.0) No support (Yes) (Yes)
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
EventSource support 4.4 45 No support 12 4.1
Available in shared and dedicated workers[1] (Yes) 53.0 (53.0) No support (Yes) (Yes)

[1] But not service workers as yet.

See also