var book = {            _year: 2004,            edition: 1        };        Object.defineProperty(book, "year", {            get: function () {                return this._year;            },            set: function (newValue) {                if (newValue > 2004) {                    this._year = newValue;                    this.edition += newValue - 2004;                }            }        });        book.year = 2005;        alert(book.edition);//2

        var book = {};        Object.defineProperties(book, {            _year: {                value: 2004            },            edition: {                value: 1            },            year: {                get: function () {                    return this._year;                },                set: function (newValue) {                    if (newValue > 2004) {                        this._year = newValue;                        this.edition += newValue - 2004;                    }                }            }        });