Simple d3.js Bullet Chart example

This is a simple example of a bullet chart derived from Mike Bostock's example.

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin: auto;
  padding-top: 40px;
  position: relative;
  width: 800px;
}

button {
  position: absolute;
  right: 40px;
  top: 10px;
}

.bullet { font: 10px sans-serif; }
.bullet .marker { stroke: #000; stroke-width: 2px; }
.bullet .tick line { stroke: #666; stroke-width: .5px; }
.bullet .range.s0 { fill: #eee; }
.bullet .range.s1 { fill: #ddd; }
.bullet .range.s2 { fill: #ccc; }
.bullet .measure.s0 { fill: steelblue; }
.bullet .title { font-size: 14px; font-weight: bold; }
.bullet .subtitle { fill: #999; }

</style>
<button>Update</button>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>
<script src="bullet.js"></script>
<script>

var margin = {top: 5, right: 40, bottom: 20, left: 120},
    width = 800 - margin.left - margin.right,
    height = 50 - margin.top - margin.bottom;

var chart = d3.bullet()
    .width(width)
    .height(height);

d3.json("bulletdata.json", function(error, data) {
  var svg = d3.select("body").selectAll("svg")
      .data(data)
    .enter().append("svg")
      .attr("class", "bullet")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
    .append("g")
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
      .call(chart);

var title = svg.append("g")
      .style("text-anchor", "end")
      .attr("transform", "translate(-6," + height / 2 + ")");

title.append("text")
      .attr("class", "title")
      .text(function(d) { return d.title; });

title.append("text")
      .attr("class", "subtitle")
      .attr("dy", "1em")
      .text(function(d) { return d.subtitle; });

d3.selectAll("button").on("click", function() {
    svg.datum(randomize).call(chart.duration(1000));
  });
});

function randomize(d) {
  if (!d.randomizer) d.randomizer = randomizer(d);
  d.markers = d.markers.map(d.randomizer);
  d.measures = d.measures.map(d.randomizer);
  return d;
}

function randomizer(d) {
  var k = d3.max(d.ranges) * .2;
  return function(d) {
    return Math.max(0, d + k * (Math.random() - .5));
  };
}

</script>
</body>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js