This will produce a popup window with the desired effect:

Code:
<script language="javascript">
<!-- Kristopher Wilson
var x = null;
function PopUp(url,name,width,height,left,top,scroll,toolbar,resize){
settings =('height='+height+',width='+width+',top='+top+',left='+left
+',scrollbars='+scroll+',toolbar='+toolbar+',resizable='+resize)
x = window.open(url,name,settings)
}
-->
</script>

<!-- use -->
<a href="#null" onclick="PopUp('http://www.yahoo.com','yahoo',200,200,10,10,'no','no','no')">click</a>
This is the best I know how to do. It will work for IE and NutScrape.