So Ajax is a way of developing Web applications that combines:
- XHTML and CSS standards based presentation
- Interaction with the page using DOM
- Data interchange with XML and XSLT
- Asynchronous data retrieval with XMLHttpRequest
In the traditional Web application, the interaction between the customer and the server goes like in the following way:
Visitor makes a request, Server processes request and sends data to the browser while the visitor waits, Visitor clicks on a link or interacts with the application, Server processes request and sends data back to the browser while the visitor waits.
Ultimately there is a lot of customer waiting.
Asynchronous: 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.