barchart

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <svg height="1000" width="1000">
  </svg>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.3/d3.min.js"></script>
  <script>

    let students = [
      {"name": "Jane", "value": 80},
      {"name": "John", "value": 90},
      {"name": "Bob", "value": 60}
    ];

    // TODO

  </script>
</body>
</html>