Arve Bersvendsen, on “Opera Web Applications blog” wrote about a cool new AJAX feature that wasadded to Opera 9. —With the traditional AJAX implementation, the browser continually polls the server, sending requests to the server, asking to get data back, making new HTTP requests for every single poll, putting more strain on the server than needed.

In Opera 9 you can instead open a persistent connection to the server, sending data to the client when new information is available, eliminating the need for continuous polling.

“This method for doing remoting offers a tremendous advantage, since the server no longer has to handle the overhead associated with clients asking for new data. Instead, the server simply sends back data [to]  every connected client when appropriate, thus reducing the load on the server, with the added advantage of offering instant feedback to the user.”

The new feature is called Server-Sent Events (SSE); it follows the WHATWG Web Applications 1.0 specification. See it in action.

Advantages: They seem endless, the advantages for using this new technology. This will decrease the load for servers with heavy use of AJAX. Imagine what Gmail and Google Maps can do with this.

Learn more: Opera Web Application blog | Arve Bersvendsen’s blog

Operawatch | digg

Opera takes the lead with AJAX support among browsers