javascript - How can I change the text of the back button on this dropdown pie chart? -

when click on 'recycled materials' section of pie chart drops down more info section.

the problem button has default text 'back brands' in , can't find anywhere in code change that.

my code follows:

java:

 $(function () { // create chart $('#container').highcharts({     credits: {         enabled: false     },     chart: { plotbackgroundcolor: null,             plotborderwidth: null,             plotshadow: false,         type: 'pie'     },     title: {         text: 'green amount recycled'     },     subtitle: {         text: 'click recycled materials slice more information.'     },    plotoptions: {             pie: {                 allowpointselect: true,                 cursor: 'pointer',                 datalabels: {                     enabled: false                 },                 showinlegend: true             }         },     tooltip: {         headerformat: '<span style="font-size:11px">{series.name}</span><br>',         pointformat: '<span style="color:{point.color}">{point.name}</span>: <b>{point.y:.2f}%</b> of total<br/>'     },     series: [{         name: "brands",         colorbypoint: true,         data: [{             name: "landfill - 45,821 lbs",             y: 23.73,         }, {             name: "recycled materials - 147,276 lbs",             y: 76.27,             drilldown: "recycled materials"         }]     }],     drilldown: {         series: [{             name: "recycled materials",             id: "recycled materials",             data: [                 ["tent frames , chairs - 6,400 lbs", 4.35],                 ["aluminum cans - 28,950 lbs", 19.66],                 ["plastic pet bottles - 36,420 lbs", 24.73],                 ["glass - 40,950 lbs", 27.8],                 ["cardboard - 30,000 lbs", 20.37],                 ["solo cups - 4,556 lbs", 3.09],             ]         }]     } }); }); 

html:

    <script src="http://code.highcharts.com/highcharts.js"></script>     <script src="http://code.highcharts.com/modules/exporting.js"></script>     <script src="http://code.highcharts.com/modules/data.js"></script>     <script src="http://code.highcharts.com/modules/drilldown.js"></script> <div id="container" style="min-width: 500px; max-width: 500px; height: 400px; margin: 0 auto"></div> 

thanks help!

simply change

name: "brands" 

to whatever have, maybe "materials", example