D3 Examples - NVD3 Sparkline doesn't work...

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<!DOCTYPE html>
<meta charset="utf-8">
<link href="https://nvd3.org/src/nv.d3.css" rel="stylesheet" type="text/css">
<style>
​
#chart1 {
  width: 350px;
  height: 50px;
  font-size: 14px;
  margin-top: -6px;
}
​
h2, p {
  float: left;
}
​
</style>
<body>
​
<h2>SparklinePlus:</h2>
<p><svg id="chart1" class="sparkline"></svg></p>
​
<script src="https://d3js.org/d3.v3.min.js"></script>
<script src="https://nvd3.org/nv.d3.js"></script>
<script>
​
d3.text("monthly.csv", function(data) {
    var data1 = d3.csv.parse(data);
    var parseDate = d3.time.format("%Y-%m").parse;
    data1.forEach(function(d) {
        d.Month = parseDate(d.Month);
    });
    nv.addGraph(function() {
      var data = formatMonthlyData(data1);
      var chart = nv.models.sparklinePlus()
      chart
        .margin({left:70})
        .x(function(d,i) { return i })
        .xTickFormat(function(d) {
          return d3.time.format('%x')(new Date(data[d].x))
        })
      d3.select("#chart1")
          .datum(data)
        .transition().duration(250)
          .call(chart);
      return chart;
    });
​
});
function formatMonthlyData(data) {
  var monthlyData = [];
​
  for (var i = 0; i < data.length; i++) {
    monthlyData.push({x: data[i].Month, y: +data[i].Data});
  }
​
  return monthlyData;
}
​
</script>
​
    