The documentation briefly mentioned supporting audio assets [1], but I haven't been able to find obvious examples of how to use them once they've been loaded. One of the provided sample games [2] had a soundtrack, so I dug through the source [3] a bit and discovered that there is an "Audio" class and some other undocumented functions that can be used with an "Assets" object to achieve playback. Looks like he's just coding to fast to keep everything written down. :)

[1] http://jawsjs.com/docs/symbols/jaws.Assets.html [2] http://ippa.se/webgames/unexpected_outcome/ [3] http://ippa.se/webgames/unexpected_outcome/game.js