updating chart

HTML

<div id="testUpdating" style="width: 500px; height: 200px;"></div>
<button>test</button>
<button>test</button>

JavaScript

dojo.require("dojox.charting.Theme");
dojo.require("dojox.charting.scaler.linear");
dojo.require("dojox.charting.Chart2D");
dojo.require("dojox.lang.functional");

dojo.require("dojox.charting.themes.PlotKit.orange");

var chart, limit = 100, magnitude = 70;

var randomValue = function(){
  return Math.random() * magnitude;
};

var makeSeries = function(len){
    var s = [];
    do{
        s.push(randomValue());
  }while(s.length < len);
    return s;
};

var seriesA = makeSeries(limit);
  
var updateSec = function(){
  seriesA.shift();
  seriesA.push(randomValue());
  chart.updateSeries("Series A", seriesA);

  
  chart.render();
  
};


var makeUpdateableObjects = function() {
  chart = new dojox.charting.Chart2D("testUpdating");
  chart.setTheme(dojox.charting.themes.PlotKit.orange);
     chart.addAxis("x", {natural: false, min: 1, max: limit});
  chart.addAxis("y", {vertical: true, min: 0, majorTickStep: 5, minorTickStep: 1});
  chart.addPlot("default", {type: "Areas"});
  chart.addSeries("Series A", seriesA);
  chart.addPlot("grid", {type: "Grid", hMinorLines: true});
  chart.render();
    setInterval(function (){updateSec()}, 1000);  
};

dojo.addOnLoad(makeUpdateableObjects);