function new_win(target)
{
  var win = window.open(target, "", "toolbar=no,status=no,scrollbars=yes,resizable=no,width=500,height=400,top=20,left=20");

  if (win.history.length >= 1)
  {
    var del = -win.history.length;
    win.history.go(del);
  }
}