``` 構造函數模式用于定義實例屬性，而原型模式用于定義方法和共享的屬性 每個實例都會有自己的一份實例屬性的副本，但同時又共享著對方法的引用，最大限度地節省了內存。 ``` ``` function Person(name, age, job){ this.name = name; this.age = age; this.job = job; this.friends = ["Shelby", "Court"]; } Person.prototype = { constructor : Person, sayName : function(){ alert(this.name); } } var person1 = new Person("Nicholas", 29, "Software Engineer"); var person2 = new Person("Greg", 27, "Doctor"); person1.friends.push("Van"); alert(person1.friends); //"Shelby,Count,Van" alert(person2.friends); //"Shelby,Count" alert(person1.friends === person2.friends); //false alert(person1.sayName === person2.sayName); //true ```