How to show thickbox popup onchange event of combo box

How to show thickbox popup onchange event of combo box

Hy to all,

I have used thickbox with the html link link <a href="..url.." class="thickbox" >Test</a>

But how we can popup a thickbox on change event of combo box

<select name=test id=test>

<option value=1>Value1</option>
<option value=2>value2</option>

</select>

i want to popup the thickbox on change event of this combo box.

is it possible and how

regards.