如何在highcharts中访问plotBands的特定属性？

Question

    var pB=[];  //later I have assigned **plotBands: pB,**
    pB[i]={
        from:tA[i],
        to: tA[i+1],
        label: { 
        text: wA[i], // Content of the label. 
        align: 'center'},
        color: '#eef',
        events: {
            click: function(){

                console.log("from: "+this.from);

                console.log("duration: "+this.(to-from));
            }
       }
    }

我想在每个pB [i]中访问上例中的 from 值。我怎么做 ？ 来自有一个数值。enter code here console.log（“from：”+ this.from）; 输出“undefined”。