Multiple SOAP request using Javascript

All

I am using my SOAP API using java script.

this example explain how to send single soap request using js

var symbol = "MSFT"; 
var xmlhttp = new XMLHttpRequest();
xmlhttp.open("POST", "http://www.webservicex.net/stockquote.asmx?op=GetQuote",true);
xmlhttp.onreadystatechange=function() {
 if (xmlhttp.readyState == 4) {
  alert(xmlhttp.responseText);
  // http://www.terracoder.com convert XML to JSON 
  var json = XMLObjectifier.xmlToJSON(xmlhttp.responseXML);
  var result = json.Body[0].GetQuoteResponse[0].GetQuoteResult[0].Text;
  // Result text is escaped XML string, convert string to XML object then convert to JSON object
  json = XMLObjectifier.xmlToJSON(XMLObjectifier.textToXML(result));
  alert(symbol + ' Stock Quote: $' + json.Stock[0].Last[0].Text); 
 }


}
xmlhttp.setRequestHeader("SOAPAction", "http://www.webserviceX.NET/GetQuote");
xmlhttp.setRequestHeader("Content-Type", "text/xml");
var xml = '<?xml version="1.0" encoding="utf-8"?>' +
 '<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ' +
                'xmlns:xsd="http://www.w3.org/2001/XMLSchema" ' +
                'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">' + 
   '<soap:Body> ' +
     '<GetQuote xmlns="http://www.webserviceX.NET/"> ' +
       '<symbol>' + symbol + '</symbol> ' +
     '</GetQuote> ' +
   '</soap:Body> ' +
 '</soap:Envelope>';
xmlhttp.send(xml);
// ...Include Google and Terracoder JS code here...

Now i want to send multiple soap request at a time (mean request more than one envelop).