function getCookieValue(cookieName) {
    var cookieValue = document.cookie;
    var cookieStartsAt = cookieValue.indexOf(" " + cookieName + "=");
    if (cookieStartsAt == -1) {
        cookieStartsAt = cookieValue.indexOf(cookieName + "=");
    }
    if (cookieStartsAt == -1) {
        cookieValue = null;
    }
    else {
        cookieStartsAt = cookieValue.indexOf("=", cookieStartsAt) + 1;
        var cookieEndsAt = cookieValue.indexOf(";", cookieStartsAt);
        if (cookieEndsAt == -1) {
            cookieEndsAt = cookieValue.length;
        }
        cookieValue = unescape(cookieValue.substring(cookieStartsAt, cookieEndsAt));
    }
    return cookieValue;
}