I have seen some of the documentation on `addEventListener()`, but I didn't understand the purpose of the second and third arguments of the same function. Please explain it with reference to the following code:

```
// Handle keyboard controls
var keysDown = {};

addEventListener("keydown", function (e) {
    keysDown[e.keyCode] = true;
}, false);

addEventListener("keyup", function (e) {
delete keysDown[e.keyCode];
}, false);

```