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);//1 undefine 2 3
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原文：https://www.cnblogs.com/hmy-666/p/14431774.html
