======= -->

            <!-- ========= show JS code v4 ==============  -->
            <pre
              class="language-js d-none d3v4-chunk"
            ><code id="code-js-v4" contenteditable="true"><xmp><script>

// set the dimensions and margins of the graph
var margin = {top: 10, right: 30, bottom: 30, left: 40},
    width = 460 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;

// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
  .append("s