js继承模式

<script>
        function SuperType(name){
            this.name = name;
            this.colors = ["red","blue"];
        }
        SuperType.prototype.sayName = function(){
            alert(this.name);
        }
        function SubType(name,age){
            //继承属性
            SuperType.call(this,name);
            this.age = age;
        }
        //继承方法
        SubType.prototype = new SuperType();
        SubType.prototype.constructor = SubType;
        //添加方法
        SubType.prototype.sayAge = function(){
            alert(this.age);
        }
        var instance1 = new SubType("jie",23);
        instance1.colors.push("green");
        alert(instance1.colors);
        instance1.sayName();
        instance1.sayAge();

        var instance2 = new SubType("fei",23);
        alert(instance2.colors);
        instance2.sayName();
        instance2.sayAge();

    </script>