2D Canvas: low-level, 2D graphics rendering - HTML5 in Action - page 266

Step 3: Create a Welcome screen
The first step to making a Welcome screen is adding a new object called Screen (in the
following listing) right below your Game object. The screen needs a background with a
width and height large enough to cover everything. It should say “CANVAS RICOCHET”
and “Click To Start.”
Listing 6.19. game.js—Creating the Welcome screen and listener
Your Welcome screen needs a click event listener added into a new method called
Game.setup() . Also, Game.init() needs to be modified so it fires from the new
screen listener. In addition, with the next listing, you'll make the listener reusable by adding
its logic into a new Game.runGame() method.