This is a very useful script if you are working with an image map or frame that continues to open a new browser window no matter what you do. First off -- here's the script. Copy and paste right from here.

<p align="center">
<script language="JavaScript">

<!--
{
self.name='headwin';
}
//-->

</script>

     Place that script in a page and it names the page as a target. Then make a point of targeting all your HREF links as TARGET="headwin.

     That tricks the browser into thinking it is opening in a new window when in fact -- it is opening the same window as a new target. Clever.