Highcharts Demo

http://stackoverflow.com/questions/38216837/mixed-grid-style-in-highcharts

by J. Albert Bowden

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>

<div id="container" style="height: 400px"></div>

JavaScript

$(function () {
    $('#container').highcharts({
        xAxis: {
            tickInterval: 24 * 3600 * 1000, // one day
            type: 'datetime'
        },

        yAxis: {
            plotLines: [{
                color: 'gray',
                width: 1,
                value: 216.4,
                label: {
                    text: 'max'
                }
            },{
                color: 'gray',
                width: 1,
                value: 29.9,
                label: {
                    text: 'min'
                }
            },{
                color: 'gray',
                width: 1,
                value: 135.6,
                label: {
                    text: 'median'
                }
            }],
                gridLineDashStyle: 'longdash'
        },

        series: [{
            data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4],
            pointStart: Date.UTC(2010, 0, 1),
            pointInterval: 24 * 3600 * 1000
        }]
    });
});