background-canvas-interactive-iframe-background.html

<!DOCTYPE html>
<html>
  <head lang="en">
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <style>
      html, body {
          margin: 0;
          height: 100%;
      }
      canvas {
        width: 100%;
        height: 100%;
        display: block;
      }
    </style>
  </head>
  <body>
    <canvas></canvas>
  </body>
  <script src="js/background-canvas-interactive.js"></script>
</html>