Our first bit of Javascript code is to get a reference to the canvas and then draw a circle meant to represent a ball, all of this inside a function that will be called by pressing a button to start the game.

Explanation

Talk about jQuery. Add some jQuery window.

Get ahead of me!

Next, I will remove some hard coded values (such as 200, 32) and replace them by named variables, introduce a second function, init(), used to initialized the variables, and a third, draw_ball(), specifically introduced to draw a ball.

Can you do this before I do?

If so, you might want to save your solution by clicking on the image above, before moving on to the next section and thus be ready to compare your solution with mine.