var inherits = require("util").inherits; 
function a(){
this.name = "lee"
}
a.prototype.sex = "male"
function b(){
this.color = "red"
}
b.prototype.height = "168"
function c(){
}
inherits(c,a)
inherits(c,b)
var c = new c()
console.log(c.height)
console.log(c.sex)
console.log(c.name)
 

b. 輸出：

168
undefined
undefined

function a(){
this.name = "lee"
}
a.prototype.sex = "male"
function b(){
this.color = "red"
}
b.prototype.height = "168"
function c(){
}
c.prototype = new a()
c.prototype = new b()
var c = new c()
console.log(c.height)
console.log(c.sex)
console.log(c.name)
 

b. 輸出：

168
undefined
undefined

1、只支持單繼承
2、不能作用於類本身的屬性或方法（只支持prototype原型創建的屬性或方法）

不推薦使用