function openPopupWindow(url,windowname,properties) {
  if (properties.length == 0) {
    properties = 'toolbar=no,scrollbars=yes,menubar=no,statusbar=no,width=450,height=450,resizable=1,left=100,top=100,screenX=100,screenY=100';
  }
  popupWindow = window.open(url,windowname,properties);
}