You can find the sequencer here.

I was bored today so I built a 16-step sequencer in javascript which uses sounds from 5 different instruments that I ripped from Reason. I was planning on using the HTML5 tag for audio playback but codec support is inconsistent across browsers – Chrome, Firefox, and Opera support Ogg audio, Safari supports AAC through quicktime and IE doesn’t have <audio> tag support at all. Instead of encoding audio in a bunch of different formats or using flash, I decided to use SoundManager2 which wraps the HTML5 audio api and uses flash as a failsafe. Since this is just a toy project, I didn’t mix the audio as you’d get in a real sequencer so you’ll occasionally notice clipping and samples playing off-beat. I wouldn’t recommend HTML5 audio or the above library for time-sensitive playback since you can’t get very low latency.