How can I access widgets in a seperate javascript file

asked 2013-03-05 09:34:29 +0800

shenjie
47 ● 2

this is my zuml code:
<window>
<script type="text/javascript" src="control.js" defer="true"></script>
<div id="div2">div2</div>
</window>
how can get the widget whose id is div2,the zk Client-side Reference.pdf tells me that I can use zk.Widget.$('div2'),I have trid,but it returns null.

thanks for your help and sorry for my poor English