Sencha
+Welcome to the Ext JS 4!
+Ext JS 4 is a pure JavaScript application framework that works everywhere from IE6 to Chrome 11. It enables you to create the best cross-platform applications using nothing but a browser, and has a phenomenal API.
+This is the biggest upgrade we've ever made to Ext JS and we think you're going to love it.
+ +What’s New
+We have also been posting summaries of new features and changes to our blog:
+ + + + +Upgrading
+Sencha also offers training courses and professional services for companies wishing to use Ext JS 4.
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