Unity or HTML5 game dev for simple 2d multiplayer browser game

I want to create a simple multiplayer musical chairs game. It will be played on the browser. Each game round will hold 100 players. The game will start off with 80 chairs, the music will then start and will run for a random amount of time (15-45 secs), once the music stops players then must type in a code. The fastest players will go on to the next stage and the slowest 20 players are eliminated. This continues till we have 1 winner