function checkform(f)
  {
  if(f.nome.value == '')
    {
    alert('Insert your name and surname');
    f.nome.focus();
    return false;
    }
  if(f.email.value == '')
    {
    alert('Insert your email');
    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.richiesta.value == '')
    {
    alert('Inser a short description for your request');
    f.richiesta.focus();
    return false;
    }
  if(f.vericode.value != '')
    {
    alert('Insert the spam control code that appears in the red box below');
    f.vericode.focus();
    return false;
    }
  return true;
}