function checkform(f)
  {  
  if(f.dal.value == 'dd/mm/yyyy')
    {
    alert('Insert the date of arrival');
    f.dal.focus();
    return false;
    }
  if(f.al.value == 'dd/mm/yyyy')
    {
    alert('IInsert the date of leaving');
    f.al.focus();
    return false;
    }
  if(f.adulti.value == '')
    {
    alert('Insert adults number');
    f.adulti.focus();
    return false;
    }
  if(f.bambini.value == '')
    {
    alert('Insert children number');
    f.bambini.focus();
    return false;
    }       
  if(f.nome.value == '')
    {
    alert('Insert name and surname');
    f.nome.focus();
    return false;
    }
  if(f.indirizzo.value == '')
    {
    alert('Insert your address');
    f.indirizzo.focus();
    return false;
    }
  if(f.cap.value == '')
    {
    alert('Insert your city and ZIP code');
    f.cap.focus();
    return false;
    }    
  if(f.telefono.value == '')
    {
    alert('Insert your phone number');
    f.nome.focus();
    return false;
    }  
  if(f.email.value == '')
    {
    alert('Insert your email address');
    f.email.focus();
    return false;
    }
  if(f.email.value.search(/^([\w\.\-])+@(([\w\-]{2,})+\.)+([a-z0-9]{2,})+$/i) == -1)
    {
    alert('Email format not correct');
	  f.email.focus();
    return false;
    }
  if(f.vericode.value != '1fc3')
    {
    alert('Insert the control code in the red box below');
    f.vericode.focus();
    return false;
    }
  return true;
}