Owing to the Web 2.0 era and AJAX playing an important role, many companies and communities are focusing on bringing the Desktop Experience on to the Web Browser and this has given rise to many Javascript Frameworks which help developers to build AJAX based applications quickly.
The ones featured in this comparison are:
2. Yahoo’s YUI
3. DOJO
4. Prototype (inspired by Ruby on Rails)
5. Mochikit
6. JQuery
Among them the ones that stand out in terms of features, popularity, support according to me are Google, Yahoo and DOJO, but the others too are good.
1. Kabuki AJAX toolkit from Zimbra. They have a Network and an Open Source Edition.
I was rather surprised that they did not mention about Script.aculo.us which seems to be a very mature Javascript framework. If I am not mistaken, Prototype uses the script.aculo.us framework.
Good luck and happy AJAXING and AJAXIFYING the WEB.