Invoke web service using Javascript

<script type="text/jscript" language="javascript">
    var xmlHttp;
    function SoapCall() {
        // creatng the xmlHttp object
        var xmlHttp;
        if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
            xmlHttp = new XMLHttpRequest();
        }
        else {// code for IE6, IE5
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        // Calling the web service using post and true means asynchronous call
        xmlHttp.open("post", "http://www.webservicex.net/CurrencyConvertor.asmx", false);
        // Setting the request header to let the web service identify the soap request we would be sending

        xmlHttp.setRequestHeader("Content-Type", "text/xml;charset=utf-8");

        xmlHttp.setRequestHeader("SOAPAction", "http://www.webserviceX.NET/ConversionRate");

        var soapRequest = '<?xml version="1.0" encoding="utf-16"?>' +
'<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">' +
  '<soap:Body>' +
    '<ConversionRate xmlns="http://www.webserviceX.NET/">' +
      '<FromCurrency>AFA</FromCurrency>' +
      '<ToCurrency>AFA</ToCurrency>' +
    '</ConversionRate>' +
  '</soap:Body>' +
'</soap:Envelope>';

        xmlHttp.send(soapRequest);
        alert(xmlHttp.responseText);
    }
    </script>