ElementStacks

HTML

<script src="http://highcharts.com/js/testing.js"></script>
<div id="container" style="height: 300px"></div>
<script src="http://code.highcharts.com/highcharts.src.js"></script>
<button id="b1">1st series to front</button>
<button id="b2">2nd series to front</button>

JavaScript

$(function () {
    var chart = new Highcharts.Chart({
    
        chart: {
            renderTo: 'container',
            borderWidth: 1,
            plotBorderWidth: 1,
        },    
    
        xAxis: {
            categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
        },
    
        series: [{
            type: 'column',
            data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]
        },{
            data: [ 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4,22]
        }]
    
    });
    
    $('#b1').click(function(){
        chart.series[0].update({
            zIndex: 10  
        }, false);    
        chart.series[1].update({
            zIndex: 1  
        }, true);    
    });
    
    $('#b2').click(function(){
        chart.series[0].update({
            zIndex: 1 
        }, false);    
        chart.series[1].update({
            zIndex: 10  
        }, true);       
    });
    
    
});