What do you mean by "it doesn't work"? When I try it, the game loads but immediately says:
Simply Snake
Highscore: 0 | Score: 0
GAME OVER!
Your score was: 0
You got a new highscore: 0
Is that what you mean?
If yes, it might have something to do with the fact that a bunch of Javascript and CSS isn't loading. You probably uploaded index.html without them. Please double-check.