jo is a lightweight JavaScript framework designed for HTML5 apps.

A unified user interface system across all popular mobile device platforms, built on the rock-solid jQuery and jQuery UI foundation. Its lightweight code is built with progressive enhancement, and has a flexible, easily themeable design

It’s like a virtual graffiti wall, a community bulletin board, and a poster-covered lightpost, all rolled into one. Using the GPS in your iPhone, it shows you messages that other people have left at the place you’re standing, and it lets you leave your own messages, too. It’s anonymous unless you decide to share more. You can even privately reply to other users while still remaining anonymous.