testBarLineOverlay

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.1.3/Chart.min.js"></script>
<div>
<canvas id="test" width="200" height="125"></canvas>
</div>

JavaScript

var testChart = document.getElementById("test");
var chart = new Chart(testChart, {
  type:    'bar',
  data:    {
    labels:   [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15],
    datasets: [
      {
        type:                      'line',
        fill:                      false,
        label:											'testline',
        tension:                    0,
        backgroundColor:           "rgba(0,0,0,0.1)",
        borderColor:               "rgba(0,0,0,1)",
        borderWidth:                3,
        pointRadius:                0,
        pointHoverRadius:           0,
        pointHitRadius:             0,
        hitRadius:                  0,
        pointBorderWidth:           0,
        pointBorderColor:           "rgba(255,255,255,0)",
        data:                       [2800,2680,2565,2450,2335,2220,2105,1990,1875,1760,1645,1530,1415,1300]
      },
      {
        type:                      'bar',
        label:                     "testbar",
        fill:                      false,
        lineTension:               0,
        backgroundColor:           "rgba(75,192,192,0.4)",
        borderColor:               "rgba(75,192,192,1)",
        pointHitRadius:             0,
        pointRadius:                0,
        pointBorderWidth:           0,
        pointBorderColor:           "rgba(0,0,0,0)",
        showLines:                  false,
        data:                        [3650,3420,3350,3070,3030,2850,2780,2700,2600,2400,2400,2400,2400]
      },
    ]
  }
 });