index.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Retro Screen Saver</title>
  <style>
    #container {
      width: 400px;
      height: 400px;
      position: relative;
      background: yellow;
    }

    #animateTB {
      width: 50px;
      height: 50px;
      position: absolute;

    }

    #animateBB {
      width: 50px;
      height: 50px;
      position: absolute;


    }
  </style>
</head>

<body>

  <div id="container">
    <img src="220px-Basketball.png" id="animateBB" alt="Basket Ball">
    <img src="product_14.png" id="animateTB" alt="Tennis Ball">
  </div>
  <button onclick="stopIt()">Stop IT!!</button>


  <script src="game.js"></script>
</body>

</html>