function validaBoletin (){

	var valid = true;
	var mail = document.getElementById('NewsletterMail').value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	
	if (document.getElementById('NewsletterName').value == '')
		valid = false;
	if (!filter.test(mail))
		valid = false;
	if (!valid)
		alert('Verifica que los campos sean validos!');
		
	return valid;
}