line chart with ChartJS

HTML

<script src="http://www.chartjs.org/assets/Chart.min.js"></script>
<canvas id="canvas" width="600" height="300"></canvas>

JavaScript

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, null, 56, 55, 40]
        }
    ]
};


var ctx = document.getElementById('canvas').getContext('2d');
var myLineChart = new Chart(ctx).Line(data, {
    tooltipTemplate: function (d) {
        if (d.value === null)
            throw '';
        else
            return d.label + ': ' + d.value;
    }
});