Flex SDK

Flex is a highly productive, open source framework for building and maintaining expressive web applications that deploy consistently on all major browsers, desktops and operating systems.

More to read from Flex SDK – Adobe Open Source

ExtJS – Cross-Browser Rich Internet Application Framework

Ext JS is a cross-browser JavaScript library for building rich internet applications. It includes:

• High performance, customizable UI widgets
• Well designed and extensible Component model
• An intuitive, easy to use API
• Commercial and Open Source licenses available

Ext JS supports all major web browsers including:

• Internet Explorer 6+
• FireFox 1.5+ (PC, Mac)
• Safari 3+
• Opera 9+ (PC, Mac)