Highcharts test tool

HTML

<script src="http://code.highcharts.com/highcharts.js"></script>
<script src="http://code.highcharts.com/modules/exporting.js"></script>

<div id="container" style="min-width: 300px; height: 300px; margin: 1em"></div>

JavaScript

function interpolate(data) {
    var resolution = 0.1,
        interpolatedData = [];
    data.forEach(function(point, i) {
        var x;
        if (i > 0) {
            for (x = data[i - 1].x + resolution; x < point.x; x += resolution) {
                interpolatedData.push({
                    x: Highcharts.correctFloat(x),
                    y: Highcharts.correctFloat(data[i - 1].y + (point.y - data[i - 1].y) *
                        ((x - data[i - 1].x) / (point.x - data[i - 1].x)))
                });
            }
        }
        interpolatedData.push(point)

    });
    return interpolatedData;
}
var data1 = [{
    x: 0,
    y: 29.9
}, {
    x: 1,
    y: 71.5
}, {
    x: 2,
    y: 106.4
}, {
    x: 3,
    y: 129.2
}, {
    x: 4,
    y: 144.0
}, {
    x: 5,
    y: 176.0
}, {
    x: 7,
    y: 148.5
}, {
    x: 8,
    y: 216.4
}, {
    x: 9,
    y: 194.1
}, {
    x: 10,
    y: 95.6
}, {
    x: 11,
    y: 54.4
}];

var data2 = [{
    x: 0.6,
    y: 42
}, {
    x: 2.35,
    y: 12
}, {
    x: 2.37,
    y: 15
}, {
    x: 4.1,
    y: 87
}, {
    x: 6,
    y: 123
}, {
    x: 8,
    y: 56
}, {
    x: 10,
    y: 70
}];



Highcharts.chart('container', {

    title: {
        text: 'Interpolated tooltips in Highcharts'
    },
    tooltip: {
        shared: true
    },

    xAxis: {
        crosshair: true
    },

    series: [{
        data: data1,
        enableMouseTracking: false
    }, {
        data: interpolate(data1),
        color: 'transparent',
        linkedTo: ':previous'
    }, {
        data: data2,
        enableMouseTracking: false
    }, {
        data: interpolate(data2),
        color: 'transparent',
        linkedTo: ':previous'
    }]

});