版本：
文件：
- https://cdn.bootcdn.net/ajax/libs/jQuery.BgSwitcher/0.4.3/jquery.bgswitcher.js
- https://cdn.bootcdn.net/ajax/libs/jQuery.BgSwitcher/0.4.3/jquery.bgswitcher.min.js
- https://cdn.bootcdn.net/ajax/libs/jQuery.BgSwitcher/0.4.3/jquery.bgswitcher.min.js.map