Traditionally, web pages have been delivered to the client only when the client requested it. For every client request, the browser initiates an HTTP connection to the web server, which then returns the data and the connection is closed. New applications involving RIA are challenging this traditional model by adopting latest technologies such as Ajax, Comet... etc

Ajax can be used to increase the performance by requesting only the changed or updated pages and Asynchronous background data transfer, there by reducing the transfer pages, reducing the latency and responsiveness.

Comet set to achieve a better solution where the server to send a message to the client when the event occurs, without the client having to ask for it. Such a client will not have to check with the server periodically;
rather it can continue with other work and work on the data generated by the event when it has been pushed by the server. We, at Saven Technologies, working at many of these technologies in real world scenarios.