function checkMail()
{
	var x = document.newsletter.email.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) return true;
	else 
	{
		alert('Incorrect email address');
		return false;
	}
}