function openHowTo(id) {
  if (id == 2) {
    window.open('howto/onestep','howto','left=20,top=20,width=540,height=600,toolbar=0,location=0,status=0,menubar=0,resizable=0');
  } else if (id == 3) {
    window.open('howto/riding','howto','left=20,top=20,width=540,height=360,toolbar=0,location=0,status=0,menubar=0,resizable=0');
  } else if (id == 4) {
    window.open('howto/trainers','howto','left=20,top=20,width=540,height=400,toolbar=0,location=0,status=0,menubar=0,resizable=0');
  } else if (id == 5) {
    window.open('howto/vendors','howto','left=20,top=20,width=540,height=600,toolbar=0,location=0,status=0,menubar=0,resizable=0');
  }
}