JS全局变量是如何工作的？

1. <script>

2. const one = 1;

3. var two = 2;

4. </script>

5. <script>

6. // All scripts share the same top-level scope:

7. console.log(one); // 1

8. console.log(two); // 2

9. // Not all declarations create properties of the global object:

10. console.log(window.one); // undefined

11. console.log(window.two); // 2

12. </script>