Some time ago I experimented with Processingjs.
I’ve been able to run a simple image selector in the default Samsung Galaxy S Android browser (v2.3.3).
The motivation was the request to develop an application for both Android and iPhone. As a developer, I hate to repeat myself, and I find ridiculous to re-write an app from scratch because of corporate policies about supporting a language or another.
Something worked, despite the low performances and the incompatibility with some browsers. I didn’t investigated much. The processing code had to be adapted, and the most annoying thing is the need to specify the media to load with special tags hidden in java comments. Quite portable. But not very flexible.