javascript - Referencing an element drawn in the main App -

i writing rally app in have rallychart , button. need access chart , modify setting on button click. button in same app container rallychart.

i tried ext. this. etc. these access specifiers not work. please me this?

sample code:

ext.define('customapp', {     extend: 'rally.app.app',     componentcls: 'app',     id: 'appid',     launch: function () {          var datepickerfrom = ext.create('ext.container', {             items: [{                 xtype: 'rallytextfield',                 fieldlabel: 'enter start date chart (mm/dd/yyyy): ',                 labelwidth: 150             }],             renderto: ext.getbody().dom,             id: 'd1'         });          this.add(datepickerfrom);         this.add(                 {                      xtype: 'rallychart',                     height: 400,                     width: 800,                     id: 'chart1',                     itemid: 'chart1',                     chartconfig: chartconfig,                     renderto: ext.getbody().dom                 }             );  button2 = {             xtype: 'rallybutton',             text: 'plot graph',             handler: function () {                 console.clear();                 console.log("clicking button");      // need access chart here or textfield data here               },             callback: function(){              }         };  this.add(button2); 

you may reference them via itemid. after itemid on element set:

 this.add(      {          xtype: 'rallychart',          height: 400,          itemid: 'mychart',          chartconfig: {//...} //... } 

it can used reference element:

this.down('#mychart')