I started out with a sample-based version in 2011 or so, but the link I posted uses synthesized sounds, in updates I made last year. Have a closer look at the javascript as referenced in index.html and take a look at dr110_synth.js
This is probably most evident if you play a roll on the snare or the handclap. A free-running LFO on the noise sources for these instruments prevents "machine-gunning" like you get when you roll a sample.
