function validForm(lang)
{
	var sociedad = document.getElementById("form_sociedad").value;
	var apellido = document.getElementById("form_apellido").value;
	var nombre = document.getElementById("form_nombre").value;
	var cargo = document.getElementById("form_cargo").value;
	var direccion = document.getElementById("form_direccion").value;
	var cp = document.getElementById("form_cp").value;
	var ciudad = document.getElementById("form_ciudad").value;
	var telefono = document.getElementById("form_telefono").value;
	var email = document.getElementById("form_email").value;
	var web = document.getElementById("form_web").value;
	var comentarios = document.getElementById("form_comentarios").value;
	
	var type = "";
	if (document.getElementById("form_type_1").checked) { type += 1; }
	if (document.getElementById("form_type_2").checked) { if (type != "") type = type + "_"; type += 2; }
	if (document.getElementById("form_type_3").checked) { if (type != "") type = type + "_"; type += 3; }
	if (document.getElementById("form_type_4").checked) { if (type != "") type = type + "_"; type += 4; }
	if (document.getElementById("form_type_5").checked) { if (type != "") type = type + "_"; type += 5; }
	if (document.getElementById("form_type_6").checked) { if (type != "") type = type + "_"; type += 6; }
	if (document.getElementById("form_type_7").checked) { if (type != "") type = type + "_"; type += 7; }
	if (document.getElementById("form_type_8").checked) { if (type != "") type = type + "_"; type += 8; }
	if (document.getElementById("form_type_9").checked) { if (type != "") type = type + "_"; type += 9; }
	if (document.getElementById("form_type_10").checked) { if (type != "") type = type + "_"; type += 10; }
	if (document.getElementById("form_type_11").checked) { if (type != "") type = type + "_"; type += 11; }
	if (document.getElementById("form_type_12").checked) { if (type != "") type = type + "_"; type += 12; }
	
	if (lang == "es") 
	{
		requiredStr = "campo obligatorio";
		formOkStr = "<br/><br/><font color='green'>El formulario ha sido enviado. Gracias.</font>";
		formErrorStr = "<br/><br/><b><font color='red'>Se produjo un error al enviar el formulario. Gracias a intentarlo más tarde.</font></b><br/>";
	}
	else if (lang == "pt") 
	{
		requiredStr = "campo obrigatório";
		formOkStr = "<br/><br/><font color='green'>O formulário foi enviado. Graças.</font>";
		formErrorStr = "<br/><br/><b><font color='red'>Houve um erro ao enviar o formulário. Obrigado, tente novamente mais tarde.</font></b><br/>";
	}
	
	var isValid = true;
	
	if (apellido == "" || apellido == requiredStr)
	{
		document.getElementById("form_apellido").value = requiredStr;
		isValid = false;
	}
	if (email == "" || email == requiredStr)
	{
		document.getElementById("form_email").value = requiredStr;
		isValid = false;
	}
	
	if (isValid == true)
	{
		new Ajax.Request("landing_form_"+lang+".php", {
			method: 'post',
			parameters: {send: "ok", sociedad: sociedad, apellido: apellido, nombre: nombre, cargo: cargo, direccion: direccion, 
				cp: cp, ciudad: ciudad, telefono: telefono, email: email, web: web, comentarios:comentarios, type: type},
			evalScripts: true,
			onComplete: function(transport) 
			{
				if (transport.responseText == "ok") 
				{
					tag(lang);
					document.getElementById("form_div").innerHTML = formOkStr;
				}
				else document.getElementById("form_div").innerHTML = formErrorStr;
				
				document.getElementById("form_div").style.height = "100px";
			}
		});
	}
}