## 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.

View the Examples Discuss Ext JS 4 on the forum

### What’s New

We have also been posting summaries of new features and changes to our blog:

- Drawing & Charting
- Anatomy of a Model
- Data Package
- Dynamic Loading and the New Class System

Learn more on sencha.com

API Docs

Release Notes

### Upgrading

First, check out our overview guide to see what has changed. A more thorough upgrade guide is under development.

Sencha also offers training courses and professional services for companies wishing to use Ext JS 4.