/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <canvas id="myCanvas" width="1024" height="728"></canvas>
  <script>
    var canvas = document.getElementById('myCanvas');
    var context = canvas.getContext('2d');
    function getMousePos(canvas, evt) {
      var rect = canvas.getBoundingClientRect();
      return {
        x: evt.clientX - rect.left,
        y: evt.clientY - rect.top
      };
    }


    context.beginPath();
    canvas.addEventListener('mousemove', function(evt) {
      var mousePos = getMousePos(canvas, evt);
      context.lineTo(mousePos.x, mousePos.y);
      context.fillStyle = 'red';
      context.fillRect(mousePos.x - 2, mousePos.y - 2, 5, 5);
      context.stroke();
    }, false);
  </script>


</body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width">
	<title>JS Bin</title>
	</head>
	<body>
	<canvas id="myCanvas" width="1024" height="728"></canvas>
	<script>
	var canvas = document.getElementById('myCanvas');
	var context = canvas.getContext('2d');
	function getMousePos(canvas, evt) {
	var rect = canvas.getBoundingClientRect();
	return {
	x: evt.clientX - rect.left,
	y: evt.clientY - rect.top
	};
	}


	context.beginPath();
	canvas.addEventListener('mousemove', function(evt) {
	var mousePos = getMousePos(canvas, evt);
	context.lineTo(mousePos.x, mousePos.y);
	context.fillStyle = 'red';
	context.fillRect(mousePos.x - 2, mousePos.y - 2, 5, 5);
	context.stroke();
	}, false);
	</script>


	</body>
	</html>