第一種寫法var stone={    weight:100}// function stone() {//     this.weight=100;// }function Bench() {    this.legth=100;    this.width=50;    this.weight=60;}Bench.prototype=stone;var b=new Bench();console.log(b);console.log(Object.getPrototypeOf(b));結果：第二種寫法：function stone() {    this.weight=100; }function Bench() {    this.legth=100;    this.width=50;    this.weight=60; } Bench.prototype=new stone;var b=new Bench();console.log(b);console.log(Object.getPrototypeOf(b));為什么會這樣，第二種前面會帶stone？？