Chart.js 图表上的叠加线

var data = {
  labels: ["January", "February", "March", "April", "May", "June", "July"],
  datasets: [{
    label: "My First dataset",
    //new option, barline will default to bar as that what is used to create the scale
    type: "line",
    fillColor: "rgba(220,220,220,0.2)",
    strokeColor: "rgba(0,0,0,0.6)",
    pointColor: "rgba(0,0,0,0.6)",
    pointStrokeColor: "#fff",
    pointHighlightFill: "#fff",
    pointHighlightStroke: "rgba(220,220,220,1)",
    datasetFill:false,
    data: [20, 20, 20, 20, 20, 20, 20]
  }, {
    label: "My First dataset",
    //new option, barline will default to bar as that what is used to create the scale
    type: "bar",
    fillColor: "rgba(220,20,220,0.2)",
    strokeColor: "rgba(220,20,220,1)",
    pointColor: "rgba(220,20,220,1)",
    pointStrokeColor: "#fff",
    pointHighlightFill: "#fff",
    pointHighlightStroke: "rgba(220,220,220,1)",
    data: [32, 25, 33, 88, 12, 92, 33]
  }]
};
var ctx = document.getElementById("canvas").getContext("2d");
var chart = new Chart(ctx).Overlay(data, {
  responsive: false
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://raw.githack.com/leighquince/Chart.js/master/Chart.js"></script>

<canvas id="canvas" width="400"></canvas>