function performSpecificOperation(sMethod, sOp1, sOp2)
  {
    var oSoapCall = new SOAPCall();
    oSoapCall.transportURI = SERVICE_URL;
    oSoapCall.actionURI = SOAP_ACTION_BASE + "/" + sMethod;
    var aParams = [];
    var oParam = new SOAPParameter(sOp1, "op1");
    oParam.namespaceURI = SOAP_ACTION_BASE;
    aParams.push(oParam);
    oParam = new SOAPParameter(sOp2, "op2");
    oParam.namespaceURI = SOAP_ACTION_BASE;
    aParams.push(oParam);
    oSoapCall.encode(0, sMethod, SOAP_ACTION_BASE, 0, null, aParams.length, aParams);
    var oSerializer = new XMLSerializer();
    document.getElementById("txtRequest").value = 
                          oSerializer.serializeToString(oSoapCall.envelope);                    
    setUIEnabled(false);
    
    //more code here
    oSoapCall.asyncInvoke(
                            function (oResponse, oCall, iError)
                            {
                              var oResult = handleResponse(oResponse, oCall, iError);
                              showSoapResults(oResult);
                            }
                          );
    
  }
  
  function handleResponse(oResponse, oCall, iError)
  {
    setUIEnabled(true);
    if (iError != 0)
    { 
      alert("Unrecognized error.");
      return false;
    }
    else
    {
      var oSerializer = new XMLSerializer();                          
      document.getElementById("txtResponse").value = 
                      oSerializer.serializeToString(oResponse.envelope);
      var oFault = oResponse.fault; 
      if (oFault != null)
      { 
        var sName = oFault.faultCode; 
        var sSummary = oFault.faultString; 
        alert("An error occurred:\n"  + sSummary
                                  + "\n" + sName
                                  + "\nSee message pane for SOAP fault");
        return false;
      }
      else
      {
        return oResponse;
      }
    }
  }
    
  function showSoapResults(oResult)
  {
    
    if (!oResult) return;       
    document.getElementById("txtResult").value = oResult.body.firstChild.firstChild.firstChild.data;
  }