function getCookie(cookieName){
    var cookieValue = '',cookie = document.cookie;
    if(document.cookie.length > 0){
        var cookieStart = cookie.indexof(cookieName + '=');
        if(cookieStart != -1){
            var cookieEnd = cookie.indexof(';', cookieStart+1);
            if(cookieEnd == -1){
                cookieEnd = cookie.length;
            }
            cookieValue = unescape(cookie.substring(cookieStart + cookieName.length + 1),cookieEnd);
        }
    }
    return cookieValue;
}

function setCookie(cookieName,cookieValue,expireDate){
    document.cookie = cookieName + '=' + escape(cookieValue) + ';expires=' + expireDate.toGMTString();
}

function deleteCookie(cookieName){
    var newDate = new Date();
    newDate.setTime(newDate.getTime() - 86400000);
    document.cookie = cookieName + '=delete;expires='+newDate.toGMTString();
}