获取cookie

 function getCookie(cookieName) {
        var strCookie = document.cookie;
        var arrCookie = strCookie.split("; ");
        for(var i = 0; i < arrCookie.length; i++){
            var arr = arrCookie[i].split("=");
            if(cookieName == arr[0]){
                return arr[1];
            }
        }
        return "";
    }