在浏览器中使用JavaScript module(模块)
目录：
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body>
<script type="module">
import { sum } from "./index.js"
const result = sum(1, 2)
console.log(result)
</script>
</body>
</html>
index.js:
export const sum = (a, b) => a + b
调试界面：
注意事项：需要把网页放到node的本地服务器里
参考链接：https://ponyfoo.com/articles/es6-modules-in-depth
