Ajax not working in wicket for me

Question

I wanted to test some AJAX DropDown in wicket 6.5 (tried wicket 6.6 and had same problems).

I created my wicket test project using quickstart wicket page - http://wicket.apache.org/start/quickstart.html

mvn archetype:generate -DarchetypeGroupId=org.apache.wicket -DarchetypeArtifactId=wicket-archetype-quickstart -DarchetypeVersion=6.6.0 -DgroupId=net.betlista -DartifactId=tests.wicket-6.6 -DarchetypeRepository=https://repository.apache.org/ -DinteractiveMode=false

I changed HomaPage to my LoadableDropDownTestPage in getHomePage() of generated WicketApplication class.

Java code for LoadableDropDownTestPage is:

package net.betlista;

import java.io.Serializable;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.IAjaxIndicatorAware;
import org.apache.wicket.ajax.form.OnChangeAjaxBehavior;
import org.apache.wicket.ajax.markup.html.form.AjaxButton;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.form.DropDownChoice;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.panel.FeedbackPanel;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.LoadableDetachableModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.model.PropertyModel;

public class LoadableDropDownTestPage extends WebPage implements IAjaxIndicatorAware {

    public LoadableDropDownTestPage() {
        addComponents();
    }

    private void addComponents() {
        add(new FeedbackPanel("feedback"));

        FormObject formObject = new FormObject();
        Form<FormObject> form = new Form<FormObject>("loadableDropDownTestForm", Model.of(formObject));
        form.setOutputMarkupId(true);
        form.setOutputMarkupPlaceholderTag(true);

        final DropDownChoice<String> countryDD = new LoadableDropDown("countryDD", new PropertyModel<String>(formObject, "country"));
        countryDD.setChoices(new CountryLoadableModel());
        countryDD.setOutputMarkupId(true);
        countryDD.setRequired(true);
        countryDD.setOutputMarkupPlaceholderTag(true);

        final DropDownChoice<String> cityDD = new LoadableDropDown("cityDD", new PropertyModel<String>(formObject, "city"));
        cityDD.setChoices(new CityLoadableModel());
        cityDD.setOutputMarkupId(true);
        cityDD.setRequired(true);
        cityDD.setOutputMarkupPlaceholderTag(true);

        countryDD.add(new OnChangeAjaxBehavior() {
            @Override
            protected void onUpdate(AjaxRequestTarget target) {
                System.out.println("country DD changed");
                target.add(cityDD);
            }
        });

        form.add(countryDD);
        form.add(cityDD);

        form.add(new AjaxButton("ab") {} );

        add(form);
    }

    static class LoadableDropDown extends DropDownChoice<String> {

        public LoadableDropDown(String id, IModel<String> model) {
            super(id);
            setModel(model);
        }

    }

    static class FormObject implements Serializable {
        String country;
        String city;
    }

    class CountryLoadableModel extends LoadableDetachableModel<List<String>> {

        @Override
        protected List<String> load() {
            System.out.println("loading CountryLoadableModel");
            List<String> result = Arrays.asList(new String[] { "CR", "SR" } );
            return result;
        }

    }

    class CityLoadableModel extends LoadableDetachableModel<List<String>> {

        List<String> choices = new LinkedList<String>();

        @Override
        protected List<String> load() {
            System.out.println("loading CityLoadableModel");
            if (choices.isEmpty()) {
                choices.add("1");
            } else {
                int size = choices.size();
                choices.add(Integer.toString(size+1));
            }

            return choices;
        }

    }

    @Override
    public String getAjaxIndicatorMarkupId() {
        return "ajaxIndicator";
    }

}

and HTML for page is:

<!DOCTYPE html>
<html xmlns:wicket="http://wicket.apache.org">

    <div wicket:id="feedback"></div>

    <form wicket:id="loadableDropDownTestForm">
        Countries: <select wicket:id="countryDD"></select><br>
        Cities: <select wicket:id="cityDD"></select><br>
        <!-- input type="submit"-->
        <button wicket:id="ab"></button>
    </form>


</html>

My very first problem is, that I couldn't see AJAX debug link on my page. But I think that while there is OnChangeAjaxBehavior I should see it.

Next problem is that when I change value in country DropDown nothing happens and I have no idea what am I doing wrong.

In my code you can see, that I tried also with AjaxButton, but that didn't work too.

edit:

part of the log (it's running in DEV mode)

********************************************************************
*** WARNING: Wicket is running in DEVELOPMENT mode.              ***
***                               ^^^^^^^^^^^                    ***
*** Do NOT deploy to your live server(s) without changing this.  ***
*** See Application#getConfigurationType() for more information. ***
********************************************************************

Answer 1

I think that the problem is that you are not using the <body> tag in your HTML. This breaks the HTML parsers and this is why you cannot see the AJAX debug window (and any other javascript behaviour).

There is a nice example of what you are trying to do at Wicket Examples, have a look at it: http://www.wicket-library.com/wicket-examples/ajax/choice