function showMail(c)
{
  var width=350;
  var height=180;
  window.open('http://www.parkon.de/?c='+c,'','width='+width+',height='+height+',toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,copyhistory=no,top='+(screen.height-height)/2+',left='+(screen.width-width)/2);
}