javascript构建自己的对象

<script type='text/javascript'>
//构建一个CustomerBooking类
//构造函数
        function CustomerBooking(bookingId,customerName,film,showDate){
            this.bookingId = bookingId;
            this.customerName = customerName;
            this.film = film;
            this.showDate =showDate;
        }
//getBookingId方法，有点奇特
        CustomerBooking.prototype.getBookingId = function(){
            return this.bookingId;
        }
//setBookingId方法
        CustomerBooking.prototype.setBookingId = function(bookingId){
            this.bookingId = bookingId;
        }
        CustomerBooking.prototype.getCustomerName = function(){
            return this.customerName;
        }
        CustomerBooking.prototype.setCustomerName = function(customerName){
            this.customerName = customerName;
        }
        CustomerBooking.prototype.getFilm = function(){
            return this.film;
        }
        CustomerBooking.prototype.setFilm = function(film){
            this.film = film;
        }
        CustomerBooking.prototype.getShowDate = function(){
            return this.showDate;
        }
        CustomerBooking.prototype.setShowDate = function(showDate){
            this.showDate = showDate;
        }
       //构建一个cineme类，属性为数组，可以保存预定信息
        function cinema(){
            this.bookings = new Array();
        }
        //addBooking方法
        cinema.prototype.addBooking = function(bookingId,customerName,film,showDate){
            this.bookings[bookingId] = new CustomerBooking(bookingId,customerName,film,showDate);
            
        }
        //getBookingsTable方法
        cinema.prototype.getBookingsTable = function(){
            var booking;
            var bookingsTableHTML="<table border=1>";
            for(booking in this.bookings){
                bookingsTableHTML +="<tr><td>";
                bookingsTableHTML +=this.bookings[booking].getBookingId();
                bookingsTableHTML +="</td>";
                
                bookingsTableHTML +="<td>";
                bookingsTableHTML +=this.bookings[booking].getCustomerName();
                bookingsTableHTML +="</td>";
                
                bookingsTableHTML +="<td>";
                bookingsTableHTML +=this.bookings[booking].getFilm();
                bookingsTableHTML +="</td>";
                
                bookingsTableHTML +="<td>";
                bookingsTableHTML +=this.bookings[booking].getShowDate();
                bookingsTableHTML +="</td></tr>";
            }
            bookingsTableHTML +="</table>";
            return bookingsTableHTML;
            
        }
        
//新建cinema对象就可以了，这里会通过addBooking自动生成customerBooking对象，
保存到cinema对象bookingFilm的属性当中，然后调用getBookingsTable方法来获取数据信息
        var bookingFilm = new cinema();
        bookingFilm.addBooking(123,"Jack","Love Java","1 May 2012");
        bookingFilm.addBooking(123,"Jack","Love Java","1 May 2012");
        bookingFilm.addBooking(122,"Jack","Love Java","1 May 2012");
        bookingFilm.addBooking(121,"Jack","Love Java","1 May 2012");
        bookingFilm.addBooking(120,"Jack","Love Java","1 May 2012");
        bookingFilm.addBooking(119,"Jack","Love Java","1 May 2012");
        document.write(bookingFilm.getBookingsTable());
        </script>