Can't post to popup, sized page

Can't post to popup, sized page

I can use standard form/post/action to a new page but I am trying to
do a window.open function but if I use:

  1. <form method="POST" action="javascript:window.open('newtest56o.php','','height=480,width=640')">

I get sized popup window but no passed info from post


If I use:
  1. <FORM  onsubmit="window.open("newtest56o.php",'Popup','width=400,height=500')" action="newtest56o.php" method="post" target="Popup">



I get 2nd full size tabbed window  with the info I needed.

I want popup small window that is focused, not full size and not tabbed
Thanks,
Ray