function A(name,age) {
    var o = new Object()
    o.name = name
    o.age = age
    o.sayName = function () {
        alert(this.name)
    }
    return o
}
var A1 = new A('qwe',18)
console.log(A1 instanceof A);  //不是A的实例吗？
console.log(A1 instanceof Object);

function B(name,age) {
    this.name = name
    this.age = age
}
var B1 = new B('asd', 12)
console.log(B1 instanceof B);
console.log(B1 instanceof Object);

请问从哪体现呢？