Reusable D3 sparkline chart with optional gradient

<html>
  <head>
    <meta charset="utf-8">
    <title>D3.js Sparkline</title>
    <style>
      path {
        stroke-width: 1;
        fill: none;
      }
      label {
        float: left;
        margin-top: 5px;
        margin-right: 5px;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <div class="container">
      <label>Ryanair stock price Feb. 2015 -> Feb. 2016</label>
      
      <div id="ryanair-stock-chart"></div>
    </div>
    <div class="container">
      <label>Easyjet stock price Feb. 2015 -> Feb. 2016</label>
      
      <div id="easyjet-stock-chart"></div>
    </div>
    
    <script src="https://d3js.org/d3.v3.min.js"></script>
    <script src="sparkline.js"></script>
    <script type="text/javascript">
      var ryanairStockChart = sparkline()
                                .width(155)
                                .height(50)
                                .gradientColors(['green', 'orange', 'red']) // top -> bottom
                                .csvFilePath('ry4c.csv') // relative to sparkline.js
                                .selector('#ryanair-stock-chart');
      var easyjetStockChart = sparkline()
                                .width(155)
                                .height(50)
                                .gradientColors(['green', 'orange', 'red']) // top -> bottom
                                .csvFilePath('ezj.csv') // relative to sparkline.js
                                .selector('#easyjet-stock-chart');
      ryanairStockChart();  // render the chart
      easyjetStockChart();
    </script>
  </body>

</html>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js