Server-sent events

Traditionally, a web page has to send a request to the server to receive new data; that is, the page requests data from the server. With server-sent events, it's possible for a server to send new data to a web page at any time, by pushing messages to the web page. These incoming messages can be treated as Events + data inside the web page.

Interfaces

EventSource
Defines all the features that handle connecting to a server, receiving events/data, errors, closing a connection, etc.

Examples

Specification

Specification Status Comment
WHATWG HTML Living Standard
The definition of 'Server-sent events' in that specification.
Living Standard

Browser compatibility

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)

[1] But not service workers as yet.

See also

Tools

Other resources

Document Tags and Contributors

 Last updated by: DomenicDenicola,