We need to add actions to respond to mouse clicks on the board. But first, we need a way to keep track of what is on each board space. There are three possibilities. It can be an X, an O or empty. We will keep track of these using an array of numbers. Since there are 9 spaces on the board, we will need 9 slots in the array. Each one will contain a 0 (zero) if it is an empty space, a 1 if it is an X and a 2 if it is an O (Oh). We will also add a function to set the array slots to 0 when the page starts and initialize some other things. This will be run when the page is loaded by making it the handler for the onLoad event for the body tag.