D3 - Data Binding 2

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { 	margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
 
    #chart {
      margin: 1em 3em;
    }
    .note {
      margin-top: 1em;
      font-size: 1.2em;
      background-color: #D8D8D8;
    }
    .bar {
      background-color: blue;
  		height: 20px;
  		margin-top: 2px;
    }
  </style>
</head>

<body>
  <div class="note">
  	<p>You need 4 properties to create a SVG rect: x, y, width, height</p>
  	<p>More at <a href="https://developer.mozilla.org/en-US/docs/Web/SVG/Element/rect">MDN Docs</a></p>
  </div>
  <svg id="chart">
    <rect/>
    <rect/>
    <rect/>
    <rect/>
    <rect/>
  </svg>
  <script>
    var rectWidth = 50;
    var chartHeight = 400;
    var chartWidth = 700;
    
    var data = [200, 60, 100, 80, 10];

</script>
</body>

https://d3js.org/d3.v4.min.js