AjaxRequestAttributes attributes = new AjaxRequestAttributes();

    AjaxCallListener listener = new AjaxCallListener();

    listener.onPrecondition("return somePrecondition();");

    listener.onAfter("alert('After!');");

    listener.onSuccess("alert('Success!');");

    listener.onFailure("alert('Failure!');");

    listener.onComplete("alert('Complete!');");

    attributes.getAjaxCallListeners().add(listener);

    AjaxRequestAttributes attributes = new AjaxRequestAttributes();

    AjaxCallListener listener = new AjaxCallListener();

    listener.onPrecondition("return somePrecondition();");

    listener.onAfter("alert('After!');");

    listener.onSuccess("alert('Success!');");

    listener.onFailure("alert('Failure!');");

    listener.onComplete("alert('Complete!');");

    attributes.getAjaxCallListeners().add(listener);

    // the following handlers are not JsonFunction and they will be wrapped in JsonFunction by Wicket and the

    // appropriate parameters will be passed.

    // For the 'before' handler it looks like: function(attrs, jqXHR, settings){Wicket.Log.info('[Wicket Ajax 6 demo]: executing a before handler');}

    // For the 'complete' handler it looks like: function(attrs, jqXHR, textStatus){Wicket.Log.info('[Wicket Ajax 6 demo]: executing a complete handler');}

    listener.onComplete("Wicket.Log.info('[Wicket Ajax 6 demo]: executing a complete handler. Status: ' + textStatus);");

    // change the return to 'false' and the Ajax call wont be executed at all.

    AjaxRequestAttributes attributes = new AjaxRequestAttributes();

    AjaxCallListener listener = new AjaxCallListener();

    listener.onPrecondition("return somePrecondition();");

    listener.onAfter("alert('After!');");

    listener.onSuccess("alert('Success!');");

    listener.onFailure("alert('Failure!');");

    listener.onComplete("alert('Complete!');");

    attributes.getAjaxCallListeners().add(listener);

    AjaxRequestAttributes attributes = new AjaxRequestAttributes();

    AjaxCallListener listener = new AjaxCallListener();

    listener.onPrecondition("return somePrecondition();");

    listener.onAfter("alert('After!');");

    listener.onSuccess("alert('Success!');");

    listener.onFailure("alert('Failure!');");

    listener.onComplete("alert('Complete!');");

    attributes.getAjaxCallListeners().add(listener);

        AjaxCallListener ajaxCallListener = new AjaxCallListener();

        ajaxCallListener.onSuccess("alert('Success');");

        ajaxCallListener.onFailure("alert('Failure');");

      }

    };

    link2.add(new AttributeAppender("class", Model.of("link2"), " "));

    Label label2 = new Label(MenuItem.CAPTION_ID, "One");

      js.append("$.blockUI( ");

    }

    js.append(options.toString()).append(" ); ");

  }

  public CharSequence getBlockElementsSelector()

  {

    return null;

    AjaxRequestAttributes attributes = new AjaxRequestAttributes();

    AjaxCallListener listener = new AjaxCallListener();

    listener.onPrecondition("return somePrecondition();");

    listener.onAfter("alert('After!');");

    listener.onSuccess("alert('Success!');");

    listener.onFailure("alert('Failure!');");

    listener.onComplete("alert('Complete!');");

    attributes.getAjaxCallListeners().add(listener);