Send a responseText to JavaScript from Struts 1.3 Action Class Method

Struts 1.3 Action class method

public ActionForward deleteIfesSystem(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws IOException {
        Integer ifesSystemKey = Integer.parseInt(request.getParameter("ifesSystemKey"));
        // Set IFES System properties
        IFESystem ifeSystem = IFESystemManager.getIFESystem(ifesSystemKey);
        String error = "OK";      
        try {
            IFESystemManager.deleteIFESSystem(ifeSystem);
        }
        catch (HibernateException e) {
            error = "IFES System cannot be deleted.";
        }      
        response.getWriter().write(error);
        response.getWriter().close();
        return null;
    }

JavaScript ajax function

function deleteOnClick() {
    if (confirm("Do you want to delete the selected IFES System?")) {
        var params = new Array();
        params.push("action=deleteIfesSystem");
        params.push("ifesSystemKey=" + ifesSystemGrid.getSelectedId());
        var request = new ServerRequest( url + params.join("&"), null, false);
        var xmlhttp = request.send();
        debugger
        if (xmlhttp.responseText == "OK") {
            ifesSystemGrid.deleteRow(ifesSystemGrid.getSelectedId());
            alert("IFES System deleted.");
        }
        else {
            alert(xmlhttp.responseText);
        }
    }
}