class是es6新增的一种语法糖，用于简化js中构造类的过程

1.es5中如何构造类？

javascript">function Person(name,age){
	this.name = name;
	this.age = age;
}
Person.prototype.sayName = function(){
	return 	this.name;
}
let p1 = new Person('小明',22);

es6class_14">2.es6中的class方式

javascript">class Person2{
	constructor(name,age){
	//实例化时会被立即调用
		this.name = name;
		this.age = age;
	}
	sayName(){
		return this.name;
	}
	sayAge(){
		return this.age;
	}
}
let p2 = new Person2('小乔',27)