JavaScript GUI Framework
<p>I want to port a standalone application to web based which run within browser. Since there are extensive windowing, I plan to use</p>

<p><a href="http://www.extjs.com/" rel="nofollow">http://www.extjs.com/</a></p>

<p>May I know besides the web GUI framework I mention above, is there any alternative? Preferable free and open source.</p>
