Server-sent events is a technology for providing push notifications from a server to a browser client in the form of DOM events. The Server-Sent Events EventSource API is now being standardized as part of HTML5 by the W3C.
The WHATWG Web Applications 1.0 proposal included a mechanism to push content to the client. On September 1, 2006, the Opera web browser implemented this new experimental technology in a feature called "Server-Sent Events".
Web browsers 
|Mozilla Firefox||Yes||Starting with Firefox 6.0 |
|Opera||Yes||Starting with Opera 11 |
|Safari||Yes||Starting with Safari 5.0 |
- Cramp - Ruby/EventMachine based server implementation for WebSocket and Server-Sent Events
- django-sse - HTML5 Server-Sent Events integration for Python/Django
- sse - Server Sent Events protocol implementation on python2 and python3 in the same codebase.
- event-source-library - Server Sent Events protocol implementation in python2 with tornado. Client and server implementations.
- SignalR - Transparent implementation for ASP.NET.
- Mojolicious - Perl real-time web framework.
- Hoa\Eventsource - PHP Server-Sent Events implementation.
See also 
- HTML5 server-sent events W3C draft specification.
- HTML5 Server-push Technologies, Part 1. Introduction into HTML5 Server-push Technologies. Part 1 covers ServerSent Events.
- Using server-sent events. Concise example how to use server-sent events, on the Mozilla Developer Network.
- Django push: Using Server-Sent Events and WebSocket with Django Django push: Using Server-Sent Events and WebSocket with Django.