<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
    </head>
    <body>
        <ul></ul>

        <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 (let i = 0; i < people.length; i++) {
                let liEl = document.createElement('li');
                liEl.innerHTML = people[i].name + ' ' + people[i].age + '岁'
                ul.appendChild(liEl)
            }
        </script>
    </body>
</html>