function Validate(formulario)
{
   
  if (formulario.Nombre.value.length < 4)
  {
    alert("Write, at least, 4 characters in the \"Name\" field.");
    formulario.Nombre.focus();
    return (false);
  }

  var checkOK = "ABCDEFGHIJKLMNÑOPQRSTUVWXYZÁÉÍÓÚabcdefghijklmnñopqrstuvwxyzáéíóú ";
  var checkStr = formulario.Nombre.value;
  var allValid = true;
  for (i = 0;  i < checkStr.length;  i++)
  {
    ch = checkStr.charAt(i);
    for (j = 0;  j < checkOK.length;  j++)
      if (ch == checkOK.charAt(j))
        break;
    if (j == checkOK.length)
    {
      allValid = false;
      break;
    }
  }
  
  if (!allValid)
  {
    alert("Write only letters in \"Name\" field.");
    formulario.Nombre.focus();
    return (false);
  }

  if ((formulario.Email.value.indexOf ('@', 0) == -1)||(formulario.Email.value.length < 5)) { 
    alert("Write valid e-mail address in \"Email\" field."); 
    formulario.Email.focus();
    return (false); 
  }
  
  if (formulario.Comentarios.value.length == 0) {
    alert("Make some comments in the \"Comment\" field."); 
    formulario.Comentarios.focus();
    return (false); 
  }

  if (formulario.privacy.checked == false) {
    alert("Accept  \"Privacy  Warning\"."); 
    formulario.privacy.focus();
    return (false); 
  }
  
  return (true);
}