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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Adjust Padding</title>
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css">
  <style>
    canvas{
      background: #000;
    }
  </style>
</head>
<body>

  <canvas id="canvas"></canvas>

  <script>
      var canvas;
      var canvasWidth;
      var ctx;

      canvas = document.getElementById('canvas');
      if (canvas.getContext) {
        ctx = canvas.getContext("2d");

        window.addEventListener('resize', resizeCanvas, false);
        window.addEventListener('orientationchange', resizeCanvas, false);
        resizeCanvas();
      }

      function resizeCanvas() {
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;
      }
  </script>

</body>
</html>