prototype是用來(lái)讓實(shí)例構(gòu)建proto的
先看一張圖
Paste_Image.png
圖中的Foo是構(gòu)造函數(shù), b和c是從Foo new出來(lái)的實(shí)例
這么一看,其實(shí)看不出proto和prototype什么差別, 仔細(xì)看, 只有構(gòu)造函數(shù)才有prototype仰担。
__proto__ is the actual object that is used in the lookup chain to resolve methods, etc.
prototype is the object that is used to build __proto__ when you create an object with new:
就是說(shuō)prototype是用來(lái)讓實(shí)例構(gòu)建proto的
( new Foo ).__proto__ === Foo.prototype
( new Foo ).prototype === undefined
