line chart with ChartJS

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.1.0/Chart.min.js"></script>
<select id="mySelect">
    <option>January</option>
    <option>February</option>
    <option>March</option>
    <option>April</option>
    <option>May</option>
    <option>June</option>
    <option>July</option>
</select> <br />

<canvas id="canvas" height="300" width="600"></canvas>

JavaScript

var data = {
    labels: ["January", "February", "March", "April", "May", "June", "July"],
    datasets: [
        {
            label: "My First dataset",
            fillColor: "rgba(220,220,220,0.5)",
            strokeColor: "rgba(220,220,220,0.8)",
            highlightFill: "rgba(151,187,205,0.75)",
            highlightStroke: "rgba(220,220,220,1)",
            data: [65, 59, 80, 81, 56, 55, 40]
        },
    ]
};

var ctx = document.getElementById('canvas').getContext('2d');
var myBarChart = new Chart(ctx).Bar(data);


function highlightBar(s) {
    // this clears off any tooltip highlights
    myBarChart.update();
    myBarChart.activeElements = [];

    // reset any coloring because of selection
    myBarChart.datasets.forEach(function (dataset) {
        dataset.bars.forEach(function (bar) {
            if (bar.selected) {
                bar.fillColor = bar.selected.fillColor;
                bar.strokeColor = bar.selected.strokeColor;
                delete bar.selected;
            }
        })
    });

    var index = myBarChart.scale.xLabels.indexOf(this.value);
    myBarChart.datasets.forEach(function (dataset) {
        var selectedBar = dataset.bars[index];

        // store the current values
        selectedBar.selected = {
            fillColor: selectedBar.fillColor,
            strokeColor: selectedBar.strokeColor
        }

        // now set the color
        selectedBar.fillColor = "red";
        selectedBar.strokeColor = "red";
    });

    myBarChart.update();
}

document.getElementById("mySelect").onchange = highlightBar.bind(document.getElementById("mySelect"));
document.getElementById("mySelect").onchange();