原型

function People(name){
 this.name = name
}
People.prototype.work = function(){console.log('工作')}
function Student(name,id){
 People.apply(this,arguments)//People.call(this,name)
 this.id = id
}
//相当于temp.prototype.\_\_proto\_\_ = People.prototype
function temp(){}
temp.prototype = People.prototype
Student.prototype = new temp()

Student.prototype.constructor = Student
Student.prototype.study = function(){console.log('学习')}

Class

class A {
 constructor(a)
 this.a = a
 do\_A(){}
}
class A extends B {
 constructor(a,b)
 super(a)
 this.b = b
 do\_B(){}
}