This sound more like you want to use javascript.

<script language=javascript>
url="www.mypage.com";
windowName="myName";
settings="toolbar=yes,location=yes,directories=yes,status=yes,menubar=
+yes,scrollbars=yes,resizeable=yes,with=100,height=100";
myWindow = window.open(url,windowName,settings);
</script>
[download]

As long as you use the same window name it will reuse the window you already have open. If that window is not open it will create the window.