Lines on Y Axis_SO

http://stackoverflow.com/questions/12728191/highcharts-stacked-column-chart-with-with-irregular-time-intervals-possible#comment17202234_12728191

HTML

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


<div id="container" style="height: 400px; min-width: 500px"></div>

JavaScript

$(function() {
         // Create the chart
        window.chart = new Highcharts.StockChart({
            chart : {
                renderTo : 'container'
            },

            rangeSelector : {
                selected : 0
            },
            navigator : {
                enabled: false
            },
            title : {
                text : 'Timeline'
            },

            yAxis : {
                title : {
                    text : 'Section Name'
                },
                labels: {
                    formatter: function() {
                        return "";
                    }
                }
            },tooltip: {
                  crosshairs:false
             },
             plotOptions: {
             series: {
                dataLabels: {
                    enabled: true,
                    formatter: function() {
                        // Can be used to show point name (if defined)
                        
                        return '';
                    },
                    y: -10
                }
            }
        },        
            series : [{
                name: 'Item1',
                color: 'blue',
                data:[
                    [Date.UTC(2011,1,24),0.72],
                    [Date.UTC(2011,2,21),0.72],
                      [Date.UTC(2011,1,19),0.72],
                    [Date.UTC(2011,2,7),0.72] 
                     ]
                
            },{
                name: 'Item2',
                color: 'green',
                data:[
                     [Date.UTC(2011,1,19),0.55],
                    [Date.UTC(2011,2,7),0.55] 
                    ]
            },{
                name: 'Item3',
                color: 'green',
                data:[
                    [Date.UTC(2011,1,19),0.68],
                    [Date.UTC(2011,2,7),0.68]
                    ]
            }]
        });
})