<div id="chartdiv" align="center"> FusionCharts. </div> 
	  <script type="text/javascript"> 
	 var chart = new FusionCharts("../Charts/DragNode.swf", "NodeChart", "600", "450", "0", "1"); 
	 chart.setDataURL("Data/DragNode4.xml");	  
	 chart.render("chartdiv"); 
  
	 chart = getChartFromId('NodeChart');  
	 if(chart ==null) 
	  alert("null"); 
	 else{ 
	  alert("not null"); 
   var xmlRtn = chart.getXMLData(); 
   chart.setDataXML(xmlRtn);	  
   chart.render("chartdiv"); 
	 }  
 </script> 
Error message : chart.getXMLData is not a function 
why getXMLData() function error?