es3设置属性不能修改

 /*es3*/
    {
        var Person =function () {
            var data ={
                name:‘zs‘,
                sex:‘男‘,
                age:18
            }
            this.get=function (key) {
                return data[key];

            }
            this.set =function (key,value) {
                if(key !==‘sex‘){
                    data[key]=value;

                }
            }

        }


        //声明一个实例
        var person = new Person();

        //读取
        console.table({
            name:person.get(‘name‘),
            sex:person.get(‘sex‘),
            age:person.get(‘age‘)
        });

        person.set(‘name‘,‘es3-cnme‘);
        person.set(‘sex‘,‘female‘);
        person.set(‘age‘,22)

        console.table({
            name:person.get(‘name‘),
            sex:person.get(‘sex‘),
            age:person.get(‘age‘)
        });

    }