function validar(formulario){

// Nom
  if(formulario.nom.value == ''){
    // informamos del error
    alert('Insert your name');
    // seleccionamos el campo incorrecto
    formulario.nom.focus();
    return false;
  }
  // Empresa
  if(formulario.empresa.value == ''){
    alert('You are a business, organization or individual?');
    formulario.empresa.focus();
    return false;
  }

  // Adreça Factura
  if(formulario.factura.value == ''){
    alert('Insert your billing address');
    formulario.factura.focus();
    return false;
  }

  // Email
  if(formulario.email.value == ''){
    alert('Insert your teu e-mail');
    formulario.email.focus();
    return false;
  }
    // Telèfon
  if(formulario.telefon.value == ''){
    alert('Insert your phone');
    formulario.telefon.focus();
    return false;
  }
  
    if(formulario.adreca.value == ''){
    alert('Insert your adress');
    formulario.adreca.focus();
    return false;
  }
  

  
  return true;
}

function newsletter(formulario){

    if(formulario.nomnws.value == ''){
    alert('Insert your name');
    formulario.nomnws.focus();
    return false;
  }
  
    if(formulario.emailnws.value == ''){
    alert('Insert your e-mail');
    formulario.emailnws.focus();
    return false;
  }
  
    if(formulario.telefonnws.value == ''){
    alert('Insert your phone');
    formulario.telefonnws.focus();
    return false;
  }
    return true;
}