function newwindow(url, width, height)
{ if (document.all)
  { var x=window.screenLeft;
    var y=window.screenTop;
    var w=window.document.body.offsetWidth;
    var h=window.document.body.offsetHeight;
  }
 else
  { var x=window.screenX;
    var y=window.screenY;
    var w=window.outerWidth;
    var h=window.outerHeight;
  }
 var cntx=x+Math.round((w-width)/2);
 var cnty=y+Math.round((h-height)/2);
 window.open(url, null, 'left='+cntx+', top='+cnty + ', width='+width+', height='+height);
}