Yes, there is a reference:
http://www.melonjs.org/tutorial/. It is at "
Part 9: Adding a title screen". At the end of every section there is an image you can click to go to a working version of the game. Right click and "view source" to grab the source code.
What they did in part 9 is make a title screen at the beginning of the game where you can press "Enter" to start the game. You can modify this so that pressing "Enter" starts the game, pressing "H" goes to the high score screen etc. Then, you should be able to modify this by triggering "Enter" or "H" through mouse clicks. There were some discussions here regarding mouse clicking events.
Hope this helps. Good luck! ^__^