版本：
文件：
- https://cdn.bootcdn.net/ajax/libs/snap.js/1.9.3/snap.css
- https://cdn.bootcdn.net/ajax/libs/snap.js/1.9.3/snap.js
- https://cdn.bootcdn.net/ajax/libs/snap.js/1.9.3/snap.min.css
- https://cdn.bootcdn.net/ajax/libs/snap.js/1.9.3/snap.min.js