Ext JS (JavaScript library)

Ext JS is a JavaScript library for building interactive web applications using techniques such as Ajax, DHTML and DOM scripting. Ext includes interoperability with jQuery and Prototype.

Ext JS provides an easy-to-use, rich user interface, much like you would find in a
desktop application. This lets Web developers concentrate on the functionality
of Web applications instead of the technical caveats.

"The Ext JS library started out as an extension to the moderately popular, yet very
powerful Yahoo User Interface library, providing what the YUI library lacked: an
easy-to-use API (Application Programming Interface), and real world widgets.
Even though the YUI Library tried to focus on the 'User Interface', it didn't contain
much that was useful right out-of-the-box."

Ext JS (JavaScript library)