Edit in JSFiddle

function Car(carname) {
  var _name = carname;
  Object.defineProperty(this, "name", {
    get: function () { return _name + " car"; },
    set: function (value) { _name = value; }
  });
}
var Output =
    {
      Write: function (msg) {
        $("#result").append(msg);
        $("#result").append("<br/>");
      }
    }


var c = new Car("McQueen");

//測試Getter
Output.Write(c.name);

//測試Setter
c.name = "Lightning McQueen";
Output.Write(c.name);

<div id="result"></div>