<script>
      var people = [
          { name: '牛油1号', id: 1, age: 20 },
          { name: '牛油2号', id: 2, age: 21 },
          { name: '牛油3号', id: 3, age: 19 },
      ]
      var ul = document.querySelector('ul');
      // 补全代码
      for (var i=0;i<3;i++){
var li =document.createElement('li');
ul.appendChild(li);
li.innerHTML=people[i].name+ ' ' + people[i].age+'岁';
      }
  </script>