问如何高亮显示散点图中的项目

EN

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

var chart = new Highcharts.Chart({

    chart: {
        renderTo: 'container',
        defaultSeriesType: 'pie'
    },

    legend: {
        enabled: true
    },

    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },

    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]  ,
        showInLegend: true
    }]
});

// Apply events to text elements (SVG) and spans within the legend (VML + modern browsers with useHTML option).
$('.highcharts-legend text, .highcharts-legend span').each(function(index, element) {
    $(element).hover(function() {
        chart.tooltip.refresh(chart.series[0].data[index]);
    },function() {
        chart.tooltip.hide();
    })
});