function verifyEmailAddress(address) {
    var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
    if (filter.test(address)) {
        return true;
    } else {
        return false;
    }
}

function validateSubmission() {
    var email = document.getElementById('subscribeEmail' + formNumber).value;
    var isValid = verifyEmailAddress(email);
    if (isValid) {
        document.getElementById('emailError').style.display = 'none';
    } else {
        document.getElementById('emailError').style.display = '';
    }
    
    return isValid;
}

function initSubscribeEmail(emailId, emailValue) {
    defaultEmailVal = emailValue;
    if (document.getElementById && emailId) {
        ele = document.getElementById(emailId);
        onEmailBlur(ele);
    }
}

function onEmailFocus(ele) {
    if (ele.value == defaultEmailVal) {
        ele.value = "";
        ele.style.color = '#000000';
    }
}

function onEmailBlur(ele) {
    if (ele.value.length == 0 || ele.value == defaultEmailVal) {
        ele.style.color = '#999999';
        ele.value = defaultEmailVal;
    }
}