In reality, Ajax is not a big revolution : it's only the combinaison of old technologies such as CSS, JS. The revolution is more on the concept it self, the new mode to take part of these technologies to create user friendly web 2.0 applications. (it's my vision...i don't like the terms ajax or web 2.0 : it's too "hype" for things which exist since 10years) Ajax is good in 2 ways : - to accelerate form submissions or make actions without obligation to send a HTTP request to your web server (see XmlHttpRequest object for Ajax). - to design pretty interfaces : drap&drop, hide part of web pages, create animations with images, text, assist users with contextual information,.... Exactly : Prototype is a good starting point to learn Ajax. You can see also the "Yahoo! User Interface Library" at https://developer.yahoo.com/yui/ or ZK Framework http://www.zkoss.org/ The Ajax Framework Rico use Prototype. In my society, we use Prototype to create dynamics menus. It's help me because it's a reliable and clean library JS..it's IE and Firefox complient. I need a single file to install prototype : prototype.js. I can do lot of things with minimal code, only by calling a few Prototype functions. Sorry, I don't understand the question.. I don't speak fluently english If interested, take look to these others examples / scripts : http://www.netvibes.com/en https://www.sitepoint.com/premium/ http://www.dhtmlgoodies.com/ http://forums.xisto.com/no_longer_exists/ For Java Developers, - Echo2 Framework : http://echo.nextapp.com/site/ - Google Web Toolkit beta : http://www.gwtproject.org/?csw=1