jQuery.xmastree is a jQuery-based free software (GPLv3) designed to provide a "christmas tree"-style status indicator (as seen on-board submarines visually displaying whether all hatches have been sealed and the ship is ready to submerge.
Normally this type of indicator is binary (true or false, open or closed) and that is indeed what the included example data.json file outlining the format assumes, but the xmastree script itself present no limitation in that regard.
Some may wonder what application this script has, outside the rather limited community of web-based submarine control interfaces, and the one example I can provide is the reason I came up with the idea in the first place:
A friend hosted his WoW Guild site, and wanted an easy way to visualize whether or not they needed more members of a certain class. Regrettably I didn't get around to implementing the idea until long after he'd stopped needing it, but it was a fun exercise so I did it anyway.
The source code is available from a bitbucket repository.