function openWindow(url, target, width, height, scrll) {
  var left = Math.round((screen.width - width)/2);
  var top = Math.round((screen.height - height)/2);

  var args = "menubar=0, scrollbars="+scrll+", titlebar=1, resizable=0,"
  + "width=" + width + ","
  + "height=" + height + ","
  + "status=0,"
  + "left=" + left + ","
  + "top=" + top + ","
  + "screenX=" + left + ","
  + "screenY=" + top;

  window.open(url, target, args )  
};