JavaScript 中，万物皆对象！但对象也是有区别的。分为普通对象和函数对象，Object ，Function 是JS自带的函数对象
function Person(name){
this.name = name;
}
Person.prototype.sayName = function(){
console.log(this.name);
};
Person.prototype.changeName = function(name){
this.name = name;
console.log(this.name);
};
var person1 = new Person('demo');
person1.sayName();
person1.changeName ('test');
console.log(person1.name);
这里我们定义了一个构造函数Person，它的每个对象都有changeName和sayName两个方法。下面我们看原型继承:
function Student(name){
var learns = [];
this.name = name;
this.learn = function(learn){
learns.push(learn );
}
}
Student.prototype = new Person();
var student1 = new Student('student-001');
student1.sayName();
Student继承了Person，所以他拥有Person的所有特性。