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
Server-Sent Events Recommendation Initial definition.

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)
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

Tools

Other resources

Document Tags and Contributors

 Last updated by: chrisdavidmills,