line chart with ChartJS

HTML

<script src="http://www.chartjs.org/assets/Chart.min.js"></script>
<canvas id="myChart" width="800" height="400"></canvas>

JavaScript

Chart.types.Line.extend({
  name: "LineAlt",
  draw: function () {
    Chart.types.Line.prototype.draw.apply(this, arguments);

    var ctx = this.chart.ctx;
    ctx.globalCompositeOperation = 'destination-over';
    ctx.fillStyle = 'rgba(0,0,255,0.2)';
    ctx.fillRect(0, 0, this.chart.width, this.chart.height);
    ctx.globalCompositeOperation = 'source-over';
  }
});

var data = {
  labels: ["January", "February", "March", "April", "May", "June", "July"],
  datasets: [
    {
      label: "My First dataset",
      fillColor: "rgba(220,220,220,0.2)",
      strokeColor: "rgba(220,220,220,1)",
      pointColor: "rgba(220,220,220,1)",
      pointStrokeColor: "#fff",
      pointHighlightFill: "#fff",
      pointHighlightStroke: "rgba(220,220,220,1)",
      data: [65, 59, 80, 81, 56, 55, 40]
    },
    {
      label: "My Second dataset",
      fillColor: "rgba(151,187,205,0.2)",
      strokeColor: "rgba(151,187,205,1)",
      pointColor: "rgba(151,187,205,1)",
      pointStrokeColor: "#fff",
      pointHighlightFill: "#fff",
      pointHighlightStroke: "rgba(151,187,205,1)",
      data: [28, 48, 40, 19, 86, 27, 90]
    }
  ]
};

var ctx = document.getElementById("myChart").getContext("2d");
new Chart(ctx).LineAlt(data);