function checkNewsletter() {
	var newsLetter = document.getElementById('newsletter');
	var newsLetterEr = document.getElementById('newsLetterEr');
	var emailFilter = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
	
	if(newsLetter.value === '') {
		newsLetterEr.style.display = 'block';
		newsLetter.focus();
		return false;
	}
	else if (!emailFilter.test(newsLetter.value)){			
		newsLetter.className = 'newsletter-error';
		newsLetterEr.style.display = 'block';
		newsLetter.focus();
		return false;
	}
	else {
		return true;
		newsLetterEr.style.display = 'none';
	}
}