EventSource

The EventSource interface is used to receive server-sent events. It connects to a server over HTTP and receives events in text/event-stream format without closing the connection.

Constructor

EventSource()

Creates a new EventSource from the given USVString.

Properties

This interface also inherits properties from its parent, EventTarget.

EventSource.onerror

Is an EventHandler being called when an error occurs and the error event is dispatched on this object.

EventSource.onmessage

Is an EventHandler being called when a message event is received, that is when a message is coming from the source.

EventSource.onopen

Is an EventHandler being called when an open event is received, that is when the connection was just opened.

EventSource.readyState Read only

An unsigned short 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.

Methods

This interface also inherits methods from its parent, EventTarget.

EventSource.close()

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

Specifications

Specification	Status	Comment
WHATWG HTML Living Standard The definition of 'EventSource' in that specification.	Living Standard

Browser compatibility

See also

• Using server-sent events