js原型测试题
<script> /*测试题1*/ function A(){ } A.prototype.n = 1 var b = new A() A.prototype = { n:2, m:3 } var c = new A() console.log(b.n,b.m,c.n,c.m) //b.n:1;b.m:undefined,c.n:2,c.m:3
//如果是写A.prototype.n=2 那么b.n:2 b.m:3 会影响原有的对象
//测试题2 var F=function (){ } Object.prototype.a = function(){ console.log('a()') } Function.prototype.b = function(){ console.log('b()') } var f= new F() f.a()//a() f.b()//无法执行b函数,报错 F.a()//a() F.b()//b() </script>