function isValidEmail(address) {
	var email=/^[A-Za-z0-9]+([_\.-][A-Za-z0-9]+)*@[A-Za-z0-9]+([_\.-][A-Za-z0-9]+)*\.([A-Za-z]){2,4}$/i;
	return(email.test(address));
}

function ckJoinMailingList(formName) {
    if (formName.email.value == "" || !(isValidEmail(formName.email.value))) {
        alert("Please input a valid email address.");
        formName.email.focus();
        return false;
    }
    return true;
}