Why the term Asynchronous ?
This is the key. In standard Web applications, the interaction between the customer and the server is synchronous. This means that one has to happen after the other. If a customer clicks a link, the request is sent to the server, which then sends the results back.
I used Ajax in PSCTrainer Search
See the website www.psctrainer.com , to know how the questions loaded while just key in data with out any delay..