__proto__
是每个对象都有的属性function instanceof(left, right){
var left = left.__proto__;
var right = right.prototype;
while(true){
if(left==null) return false
if(left==right) return true:
left = left.__proto__
}
}
只要右边构造函数的prototype在左边对象的原型链上即可
实现instanceof , prototype与 __proto__
原文:https://www.cnblogs.com/lhs-fight/p/15089336.html