Create a Javscript Program

Essentially what I need is a program which cycles through various musical stems at random. There will be 4 separate tracks (for lack of a better word) with maybe 10-15 separate audio stems within each. Each track will have a corresponding button that tells it to cycle to and play a different audio stem within the track at random. The stems or loops should repeat when finished and play until we hit a separate pause button. Each track should have its own play, and pause buttons and there should be an emblem that coincides with the progress of the track (a sort of loading button of sorts). I would send you these various audio clips/loops in mp3 form which i'd have separated by track. One track for instance, will be keyboard stems, another horns, etc. etc. The visual component or overall aesthetic can be really really simple, and i'd probably end up tweaking it a tad bit, I'd need this project to be done in Javascript as thats the language which my collaborators understand. Also, as I am still a student my budget is really tight and I probably couldn't afford more then 3 hours of your time, so please advise as to whether you think this device could be created in that amount of time. Again thanks a lot for your time and quick response. If you have a website for your services i'd really appreciate a link.