ES5中创建一个对象(或者叫做类)，通常使用构造函数定义实例属性，原型模式用于定义方法和共享属性。对象实例可以访问原型中的值，但不能修改原型中的值。
function Person(name, age) {this.name = name;this.age = age;this.friends = ['one', 'two']
}
Person.prototype = {constructor: Person,sayName: function() {alert(this.name);}
}
var p1 = new Person('ren',18);
var p2 = new Person('zhiwei', 18);
console.log(p1.friends)
console.log(p2.friends)
alert(p1.friends == p2.friends) // false new调用构造函数创建了一个新对象，所以friends数组不同ES6中引入Class概念创建一个类。
class Person {// 相当于 function Person(name, age){......}constructor(name, age) {this.name = name;this.age = age;this.friends = ['one', 'two'];}// 相当于Person.prototype = {...}sayName() {alert(this.name);}
}
let p1 = new Person('nihao', 18);
p1.sayName();
console.log(p1.friends);ES5中实现继承，通过在继承的函数中调用call()或者apply()方法实现继承
function SuperType(name) {this.name = name;this.color = ["red", "blue"];
}
SuperType.prototype.sayName = function() {alert(this.name);
}
function SubType(name, age) {SuperType.call(this, name);this.age = age;
}
SubType.prototype = new SuperType();
SubType.prototype.constructor = SubType;var s1 = new SubType('ren');
s1.sayName();
console.log(s1.color);ES6中在constructor()中调用super()可继承基类。
class SuperType {constructor(name) {this.name = name;this.color = ["red", "blue"];}sayName() {alert(this.name);}
}
class SubType extends SuperType {constructor(name, age) {// 相当于SuperType.call(this, name);super(name);this.age = age;}
}
var s1 = new SubType('ren', 19);
console.log(s1);
