Socket.IO is a universal way to write realtime web apps that work in every browser. Socket.IO supports several transports that are chosen during runtime based on the current browser capabilities:
* WebSocket
* Adobe® Flash® Socket
* AJAX long polling
* AJAX multipart streaming
* Forever Iframe
* JSONP Polling
This way it is possible to write WebSocket-like web apps without bothering much about the vendor support.
Socket.IO has an official client and various (among official) server implementations in different languages and frameworks. Here is a new Perl implementation http://github.com/vti/plack-middleware-socketio built on top of Plack as a normal middleware.
Socket.IO++