function validatenewsletter() {
    var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
    var address = document.getElementById('emailnewsletter').value;
    if (!reg.test(address)) {
        alert('Invalid Email Address');
        return false;
    }
    else {
        return true;
    }
}
function hidenewslettersection(newsletter1, newsletter2) {
    document.getElementById(newsletter1).style.display = 'none';
    document.getElementById(newsletter1).style.visibility = 'hidden';
    document.getElementById(newsletter2).style.display = 'block';
    document.getElementById(newsletter2).style.visibility = 'visible';
}
function addemailnewsletter() {
    if (validatenewsletter()) {
        var email = document.getElementById('emailnewsletter').value;
        var newslettersection = document.getElementById('newslettersection');
        var divsectionvalue = newslettersection.innerHTML;
        var xmlhttp;
        if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp = new XMLHttpRequest();
        }
        else if (window.ActiveXObject) {
            // code for IE6, IE5
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        else {
            alert("Your browser does not support XMLHTTP!");
        }
        xmlhttp.onreadystatechange = function() {

            if (xmlhttp.readyState < 4) {
                newslettersection.innerHTML = "<img src='images/loadingAnimation.gif' alt='Processing.....'/>";
            }
            if (xmlhttp.readyState == 4) {
                var value = xmlhttp.responseText;
                var index = value.indexOf("<div");
                if (index > 0) {
                    value = value.substring(0, index);
                    if (value == 'success') {
                        hidenewslettersection('newslettersectionnotsuccess', 'newslettersectionsuccess');
                    }
                    else if (value == 'exists') {
                        alert("User already Exists");
                        newslettersection.innerHTML = divsectionvalue;
                        document.getElementById('emailnewsletter').value = email;
                    }
                }
                else {
                    if (value == 'success') {
                        hidenewslettersection('newslettersectionnotsuccess', 'newslettersectionsuccess');
                    }
                    else if (value == 'exists') {
                        alert("User already Exists");
                        newslettersection.innerHTML = divsectionvalue;
                        document.getElementById('emailnewsletter').value = email;
                    }
                
                }
            }
        };
        if (email == "") {
            alert("Enter the required fields");
        }
        else {
            var url = "managenewsletteremail.aspx?email=" + email + "";
            xmlhttp.open("POST", url, true);
            xmlhttp.send(null);
        }
    }
}