Curriculum = {
    url_reload_curriculum: '', // {% url course-edit course.id %}

    get_subject1_list: function(obj) {
        df = loadJSONDoc(this.url_reload_curriculum, { action: "reload_curriculum",
                                curriculum_id: obj.value});


        df.addCallback(function(result) {
            var subject1_dropdown = getElement("id_subject1");
            replaceChildNodes(subject1_dropdown);

            forEach(result, function(item) {
                var opt = OPTION({'value': item[0]}, item[1]);
                appendChildNodes(subject1_dropdown, opt);
            });

            Curriculum.get_subject2_list(subject1_dropdown);
        });
           
    },

    get_subject2_list: function(obj) {
        df = loadJSONDoc(this.url_reload_curriculum, { action: "reload_subjects",
                                subject1_id: obj.value});


        df.addCallback(function(result) {
            var subjects_select_element = getElement("id_subjects");
            replaceChildNodes(subjects_select_element);

            forEach(result, function(item) {
                var opt = OPTION({'value': item[0]}, item[1]);
                appendChildNodes(subjects_select_element, opt);
            });
        });
    }
}