Put the following inside the <head> of your HTML :
<script language="javascript">
function ShowMenu(URL, WinTitle, WinWidth, WinHeight, WinLeft, WinTop){
attr = "resizable=no,width=" + WinWidth + ",height=" + WinHeight + ",screenX=" + WinLeft + ",screenY=" + WinTop + ",left=" + WinLeft + ",top=" + WinTop + "";
msgWindow=open(URL, WinTitle, attr);
if (msgWindow.opener == null) msgWindow.opener = self;
}
</script>
And form your link in the body as follows :
echo "
<a href=\"javascript:ShowMenu('test.php','window1',300,150,2,95)\">
This should open a new popup window sized 300 by 150 pixels.