1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title></title> 6 <script type="text/javascript"> 7 8 function Person(name , age , gender){ 9 this.name = name; 10 this.age = age; 11 this.gender = gender; 12 } 13 14 //修改Person原型的toString 15 Person.prototype.toString = function(){ 16 return "Person[name="+this.name+",age="+this.age+",gender="+this.gender+"]"; 17 }; 18 19 20 //创建一个Person实例 21 var per = new Person("孙悟空",18,"男"); 22 var per2 = new Person("猪八戒",28,"男"); 23 24 //当我们直接在页面中打印一个对象时，事件上是输出的对象的toString()方法的返回值 25 //如果我们希望在输出对象时不输出[object Object]，可以为对象添加一个toString()方法 26 //Person[name=孙悟空,age=18,gender=男] 27 /*per.toString = function(){ 28 return "Person[name="+this.name+",age="+this.age+",gender="+this.gender+"]"; 29 };*/ 30 31 var result = per.toString(); 32 //console.log("result = " + result); 33 //console.log(per.__proto__.__proto__.hasOwnProperty("toString")); 34 console.log(per2); 35 console.log(per); 36 37 38 </script> 39 </head> 40 <body> 41 </body> 42 </html>
原文：https://www.cnblogs.com/juham/p/14737003.html