through the last couple of years the web got more and more dynamic, nowadays websites and web based applications often provide a quite "rich" user interface. today it's quite easy to improve the gui of the own application/website by using one of the popular javascript frameworks. those frameworks ease the dynamic modification of the dom model, the usage of "dhtml"-features and the integration of ajax based features.
the following article gives a good overview of the most important js-frameworks:
http://en.wikipedia.org/wiki/Comparison_of_JavaScript_frameworks
"A" technology named Ajax is capable to enhance user interactions - it's
the short form of Asynchronous JavaScript and XML, so it's an incorpotation several technlogies, which are quite common and not that knew.
The "key part" is the Ajax engine between server and client. By introducing this engine the start-stop-start-stop nature of interacting with traditional websites is broken. This former is responsible for two major-task: • communicating with the server asynchronously • rendering the front end.
To provide an asynchronous communication between server and client, the descent of data needs to be bunched. In contrast to traditional webapps,
Furthermore, it's closing the gap between Desktop Apps and WebApps, enabling a more and more desktop-like experience.