UpUp 是一个免费开源的JavaScript代码，可以为站长们提供一种把网站离线到移动设备上离线访问，不要觉得这种功能需要多高的技术，其实很简单，只需要一段代码即可完成，这样可以极大的提高用户的体验度和粘合度。

　　Your users are no longer sitting at their desktops, with a wire connecting them to the internet.

　　They are visiting your site from a phone in an elevator, from their tablet on the subway, or on their laptop while they sit cramped into seat 25 E.

　　This is why modern browsers supportservice workers, a new technology which lets you serve your content to your users, even when they are offline.

　　UpUp is a free, open source project which makes using this modern magic as simple as calling one command.

　　While easy to pick up, UpUp is powerful enough to support anything from showing simple messages, to making fully functional single page applications available offline, with data customized for each of your users.