javascript - Why does my Dojo Pie chart disappear when i call updateSeries after an Ajax call? -

i trying update dojo pie chart using updateseries method. invoke method after performing ajax call updated javascript array data.

here javascript:

var eventbyreasonsdata = .... //gets populated on jsp page compile   var theme = dojox.charting.themes.julie;  var eventreasonschart = null;   function makeeventsbyreason() {      var dc = dojox.charting;     eventreasonschart = new dc.chart2d("eventsbyreasonchart");     eventreasonschart.settheme( theme ).addplot("default", {         type: "pie",         font: "normal normal 8pt tahoma",         fontcolor: "black",         labeloffset: -20,         radius: 100      }).addseries("eventseries", eventbyreasonsdata );      var anim_a = new dc.action2d.moveslice(eventreasonschart, "default");      var anim_b = new dc.action2d.highlight(eventreasonschart, "default");      var anim_c = new dc.action2d.tooltip(eventreasonschart, "default");      eventreasonschart.render();   } 

here html:

        <div id="eventsbyreasonchart" ></div> 

and here javascript making ajax call:

     new ajax.request( url, {         method: 'post',         parameters: params,         oncomplete: function(response) {               if( response.responsetext != "empty" )             {                 var chart = eventreasonschart;                  eventbyreasonsdata = response.responsetext;                  chart.updateseries( "eventseries", eventbyreasonsdata );                  chart.render();                                                              }          }     }); 

lastly, here how data formatted when being sent chart:

[{ y:48 },{ y:1 },{ y:1 },{ y:14 },{ y:7 },{ y:3 },{ y:8 }] 

when chart drawn, cool, no problems. after making ajax call, receive new data, update call made , chart disappears. no errors can see on console.

any ideas?

i suspect eventbyreasonsdata string, when updateseries() expects array. can use dojo.fromjson() convert string array:

chart.updateseries( "eventseries", dojo.fromjson(eventbyreasonsdata) );