SOURCE

var Book = function(){
    this.book = {
        "js": "好好学",
        "php": "不学了"
    }
}
var subClass = function(){
    this.name = "儿子";
}
subClass.prototype = new Book();
var test1 = new subClass();
var test2 = new subClass();
test1.book.js = "不学了";
console.log(test2.book.js);