function isValidEmailAddress(emailAddress) {
	var pattern = new RegExp(/^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i);
	return pattern.test(emailAddress);
}

function checkNewsletterForm() {
	var emailaddress = $('#emailaddress').val();
	if (!emailaddress || emailaddress == ' ') {
		alert("Please enter your email address and click on Unsubscribe");
		return false;
	}
	if (!isValidEmailAddress(emailaddress)) {
		alert("Please enter a valid email address");
		return false;
	}

	return true;
}

function unsubscribe() {
	var emailaddress = $('#emailaddress').val();
	if (!emailaddress) {
		alert("Please enter your email address and click on Unsubscribe");
		return;
	}
	if (!isValidEmailAddress(emailaddress)) {
		alert("Please enter a valid email address");
		return;
	}

	location.href='newsletter_unsubscribe.php?email='+emailaddress;
}