1 <!DOCTYPE html>
2 <html lang="en">
3
4 <head>
5 <meta charset="UTF-8">
6 <meta name="viewport" content="width=device-width, initial-scale=1.0">
7 <title>Document</title>
8 </head>
9
10 <body>
11 <script>
12
13 //需求，为stus添加一个属性，获取score分数的总和
14 var stus = {
15 scores: [
16 { name: "张三", score: 65 },
17 { name: "李四", score: 86 },
18 { name: "王五", score: 39 },
19 { name: "赵六", score: 89 },
20 ]
21 };
22
23 //为 stus 添加一个属性 total 获取总数
24 Object.defineProperties(stus, {
25 total: {
26 get: function(){
27 //声明一个变量
28 let t = 0;
29 for(let i = 0;i<this.scores.length;i++){
30 t += this.scores[i].score;//5
31 }
32 return t;
33 },
34 enumerable: true //可遍历
35 }
36 });
37
38 // console.log(stus);
39 // for(let i in stus){
40 // console.log(i);
41 // }
42
43 //得到总数
44 console.log(stus.total);
45
46 </script>
47 </body>
48
49 </html>
