A primary characteristic is the increased responsiveness and interactivity of web pages achieved by exchanging small amounts of data with the server "behind the scenes" so that entire web pages do not have to be reloaded each time there is a need to fetch data from the server. This is intended to increase the web page's interactivity, speed, functionality and usability. Description continues at WikiPedia...
We do use Ajax within Plex-XML because
- you need to fill a combo box dependent on the user input
- you want to show the description to the just entered data key
- you want to show an error message without loosing any data
- While using the asynchrony mode the user can continue to work with the website while new data is loads in the background and change the website
- The usability and responsiveness of the web application will come near to those of desktop applications