DroidScript provides a JavaScript based IDE for app development on the Andriod.
Was used to write the DroidScriptBusPirate app.
Documentation is incomplete, but better at this 3rd party wiki:
http://wiki.droidscript.me.uk/doku.php?id=start
As hardware access from browsers is sorted out, writing HTML 5 Web Apps may be a better choice.
See also: