function centerPopup(popup_name,popup_url,popup_with,popup_height,myWidth,myHeight,myScrollbar) {
  if(!myWidth) {myWidth = 10;}
  if(!myHeight){myHeight = 50;}
  if(!myScrollbar){myScrollbar = 0;}
  var popup_left = (window.screen.width/2)  - (popup_with/2 + myWidth);
  var popup_top  = (window.screen.height/2) - (popup_height/2 + myHeight);
  window.open(popup_url ,popup_name,"toolbar=no,location=no,status=no,menubar=no,scrollbars=" + myScrollbar + ",resizable=no,width=" + popup_with + ",height=" + popup_height + ",left=" + popup_left + ",top=" + popup_top + ",screenX=" + popup_left + ",screenY=" + popup_top);
}