<div class="form-group">
  <label class="control-label col-sm-2" >FMA:</label>
 <div class="col-sm-4">
    <input required type="text" id="txtFMA" name="txtFMA" pattern="[0-9]{9}" maxlength="9" minlength="9"class="form-control"
    placeholder="FMA"
   value="">
 </div>
 <section id="DatoFMA">
</section>

function validar(){
   $('#txtFMA').keyup(function(){
var _this = $('#txtFMA');
var _user = $('#txtFMA').val();
              if(_user.length == 9){
                     var res = $.ajax({
                         url: 'traslado',
                         dataType: 'json',
                         data: { miPostVar: _user },
                         type: 'post'
                     }).responseText;
                     document.getElementById("DatoFMA").innnerHTML = res;
                 }
});

    }
        setInterval(validar,1000);

protected void processRequest(HttpServletRequest request,   HttpServletResponse response)
      throws ServletException, IOException {
   response.setContentType("text/html;charset=UTF-8");

  try (PrintWriter out = response.getWriter())
  {
      FeedlotTraslado td = new FeedlotTraslado();
      this.vfma = request.getParameter("miPostVar");
        try
        {
         if(!td.ExisteFMA(Integer.parseInt(this.vfma))){

            response(response, "error");
        }
    }catch (Exception ex) {
            Logger.getLogger(trasladoDestete.class.getName()).log(Level.SEVERE, null, ex);
      }
}
 }
 private void response(HttpServletResponse resp, String msg)
     throws IOException {
    PrintWriter out = resp.getWriter();
   out.println("<h1>" + msg + "</h1>");
  }
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse     response)
     throws ServletException, IOException {
    processRequest(request, response);
 }