js继承问题

[zk3389]

function inheritPrototype(subType, superType) {
    function F() {}
    F.prototype = superType.prototype;
    subType.prototype = new F();
    subType.prototype.constructor = subType;
}

function SuperType(name) {
    this.name = name;
    this.colors = ["red", "blue", "green"];
}
SuperType.prototype.sayName = function () {
    return this.name;
};

function SubType(name, age) {
    SuperType.call(this, name);
    this.age = age;
}

inheritPrototype(SubType, SuperType);
SubType.prototype.sayAge = function () {
    return this.age;
};

var sub = new SubType("zk", 25);
console.log(sub); 

// 写了个js继承，实现了功能，继承没有问题，但通过chrome控制台看这个对象，不明白圆圈中的类型为什么不对！

[似梦飞花]

哪不对了？？？

[zk3389]

方框中的是SubType->SuperType->Object,但圆圈中的是SuperType->Object->Object