function openwin(theURL,widths,heights)
{
  tops = screen.height/2 - heights/2
  lefts = screen.width/2 - widths/2
  var win
      win = window.open(theURL,"myname","width="+widths+",height="+heights+",status=no,title=no,resizable=yes,scrollbars=yes,left="+lefts+",top="+tops);
}