function validateEmailForm(form)
	{
		var why = "";
		why += checkNotEmpty(form.nombre.value,'Nombre');
		why += checkNotEmpty(form.asunto.value,'Asunto');
		why += validateEmail(form.email.value);
		why += checkNotEmpty(form.contenido.value,'Mensaje');
		why += checkLength(form.contenido.value,'Mensaje',20);
		if (why != "") {
			alert(why);
			return false;
		}
		return true;
	}

	function checkNotEmpty(strng,campo)
	{
		var error = "";
		if (strng  == "")
		{
		  error = "Debe ingresar un valor válido para "+campo+"\n";
		}
		return error;
	}
	function checkLength(strng,campo,longitud)
	{
		var error = "";
		if (strng.length <= longitud && strng.length >0 )
		{
		  error = "El campo "+campo+" debe ser tener al menos "+longitud+" caracteres.\n";
		}
		return error;
	}

	function validateEmail(email)
	{
		var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
		if(email.match(emailRegEx))
		{
			return "";
		}else
		{
			return "Debe ingresar un valor válido para Email\n";
		}
	}

	function validateSimpleForm(form)
	{
		var why = "";
		var why1 = "";
		var why2 = "";
		var why3 = "";
		var why4 = "";
		why1 += checkNotEmpty(form.titulo.value,'Titulo');
		why2 += checkNotEmpty(form.autor.value,'Autor');
		why3 += checkNotEmpty(form.editorial.value,'Editorial');
		why4 += checkNotEmpty(form.codigo.value,'Código');
		if ((why1!="")&&(why2!="")&&(why3!="")&&(why4!=""))
		{
			why = why1 + " ó " + why2 + " ó " + why3+ " ó " + why4;
		}

		if (why != "") {
			alert(why);
			return false;
		}
		return true;
	}