高位图向下钻取不起作用

Highcharts向下钻取不起作用。场景是From图，如果我点击任何一点，它需要使用avgTimes.testIds显示另一个图（在json下面检查）。但当我点击该点时，我无法获得testId值。请检查Json和Javascript以供参考。

"this.series.data.indexOf（this.point）"代码无法获取indexValue，它给出了"undefined"作为响应。请检查javascript代码

响应json-json:

{
  "testid": {
    "name": "testId",
    "data": [
      208,
      207,
      206,
      205,
      202
    ]
  },
  "xaxis": {
    "xaxis": "xaxis",
    "data": [
      "2016/03/21  01:50:04",
      "2016/03/20  04:56:20",
      "2016/03/20  04:41:56",
      "2016/03/18  11:09:53",
      "2016/03/18  09:33:15"
    ]
  },
  "avgTimes": {
    "name": "avgTime",
    "units": "ms",
    "data": [
      1894,
      3141,
      44966,
      1792,
      22929
    ],
    "testIds": [
      208,
      207,
      206,
      205,
      202
    ]
  }
}

下面是我使用的javascript

 var options;
  var chart;
  $(document).ready(function() {
        init();
        
   });  
   
   function init() {
	    $('#back_btn').hide();
	    options = {
	      chart: {
                renderTo: 'container',
                type: 'line',
                zoomType: 'x',
            },
            title: {
                text: ''
            },
            subtitle: {
                text: ''
            },
            xAxis: {
                categories: [],
                labels: {
					align: 'center',
					x: -3,
					y: 20,
					formatter: function() {
						return Highcharts.dateFormat('%b-%d', Date.parse(this.value));
					}
				}
				
            },
            yAxis: {
                title: {
                    text: ''
                }
            },
            tooltip: {
                enabled: true,
                formatter: function() {
                    return '<b>'+ this.series.name +'</b><br/>'+
                       '<b>'+ this.x +': '+ this.y+'  '+'</b><br/>'+
                        'TestId: '+this.series.options.testIds[this.series.data.indexOf(this.point)];
                        
                }
            },
            plotOptions: {
                line: {
	                cursor: 'pointer',
                    point: {
                        events: {
                            click: function() {
	                            
                                
                                //document.write(this.series.options.testIds[this.series.data.indexOf( this.point )]);
	                            $('#dateDisplay').text(this.series.options.testIds[this.series.data.indexOf( this.point )]);
	                            
	                            $.getJSON("http://localhost:8080/reports/graph/transaction?testId="+this.series.options.testIds[this.series.data.indexOf( this.point )], function(json){
		                            
						        	options.xAxis.categories = json.xAxis.xaxisList;
                                    options.series[0] = json.avgTimes;
                                    options.series[1] = json.tps;
                                    options.series[2] = json.minTimes;
                                    options.series[3] = json.maxTimes;
					        		options.xAxis.labels = {
						        		formatter: function() {
										//return Highcharts.dateFormat('%l%p', Date.parse(this.value +' UTC'));
										return Highcharts.dateFormat('%l%p', Date.parse(this.value));
										//return this.value;
										}
					        		}
					        		
						        	options = new Highcharts.Chart(options);
						        	
						        	$('#back_btn').show();
						        	
						        });
								
	                        }
                        }
                    },
                    dataLabels: {
                        enabled: true
                    }
                }
            },
            series: [{
	                type: 'line',
	                name: '',
	                data: []
	       }]
		}
        $.getJSON("http://localhost:8080/reports/graph/tests?limit=10&offset=1&env=stg&project=MarketplaceOffers&userCount=10", function(json){
        	options.xAxis.categories = json.xaxis.data;
                options.series[0]= json.avgTimes;
                //options.series[1]=json.testid;
                //options.series[1].extra= json.testid;
                chart = new Highcharts.Chart(options);
		});
	}
   
    
    function goback() {
	    init();
	    $('#dateDisplay').text("2013-02");
	}
    

<html xmlns="http://www.w3.org/1999/xhtml">
<head> 
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> 
 <title>Dynamic Drill Down in Highcharts</title>
  <link rel="stylesheet" href="http://code.jquery.com/ui/1.10.1/themes/base/jquery-ui.css" />
  <style>
  	body,h1,h2,h3,h4,h5,h6,p,ul,ol,dl,input,textarea { font-family: 'Lucida Grande', Tahoma, Verdana, sans-serif; }  
  </style>
  
  <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
  <script src="http://code.jquery.com/ui/1.10.1/jquery-ui.js"></script>
  <script src="date.js"></script>
  <script src="dynamicChats.js"></script>
 </head>
<body>
<script src="http://code.highcharts.com/highcharts.js"></script>
<script src="http://code.highcharts.com/modules/exporting.js"></script>
<strong><div id="dateDisplay">2013-02</div></strong>
<div id="container" style="min-width: 400px; height: 400px; margin: 0 auto"></div>
<a href="#" onclick="goback();" id="back_btn">Back</a>
</body>
</html>