Time for action – restarting the game while pressing the R key

We will assign the R key as the restart key for our game. Now, let's perform the following set of steps:

1. Again, we only need to change the JavaScript file. Open the box2dcargame.js JavaScript file in a text editor.
2. We need a function to remove all the bodies:

   function removeAllBodies() {
     // loop all body list to destroy them
     for (var body = carGame.world.GetBodyList(); body != null; body = body.GetNext()) {
       carGame.world.DestroyBody(body);
     }
   }

3. We move the create world, ramp, and the car code into a function named restartGame. They were originally in the page loaded handler function:

   function restartGame() {
     removeAllBodies();
   
     // create the ground
     createGround(250, 270, 250, 25, 0);
   
     // create a ramp
     createGround(500, 250, 65, 15, -10);
     createGround(600, 225, 80, 15, -20);
     createGround(1100, 250, 100, 15, 0);
   
     // create a destination ground
     carGame.gamewinWall = createGround(1200, 215, 15,...