ElementStacks

HTML

<script src="http://highcharts.com/js/testing.js"></script>
<div id="container" style="height: 400px; width: 500px"></div>

JavaScript

var chart = new Highcharts.Chart({
    chart: {
        renderTo: 'container',
        type: 'area'
    },
    series: [{
        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]
    }]
}, function(chart){
    chart.series[0].legendSymbol.attr('height', 5)
});