Javascript 使用父级、子级和子级下拉框层叠选择

我正在使用django 1.8创建一个表单。在这个表单中，我对三个字段类型、子类型和类别使用级联选择

类型是子类型的父级

子类型是类别的父级

当我更改类型下拉框中的值时，子类型下拉框被禁用，但类别下拉框仍处于活动状态。我想知道如何禁用类别下拉框以及

当用户更改子类型下拉框时，类别下拉框将被禁用

级联选择

CascadeSelect({
    use_ajax: true,
    url: "{{ request.get_full_path }}", // The url for the ajax function
    parent: "id_project_type", // Name of the parent field in forms.py
    child: "id_sub_type", // Name of the child field in forms.py
    selected_child: "{{ selected_sub_type }}", // Sent from views.py
    empty_label_init: "Select a type first",
    empty_label_selected: "--- Please select ---",
    disable_child: true
});

CascadeSelect({
    use_ajax: true,
    url: "{{ request.get_full_path }}", // The url for the ajax function
    parent: "id_sub_type", // Name of the parent field in forms.py
    child: "id_category", // Name of the child field in forms.py
    selected_child: "{{ selected_sub_type }}", // Sent from views.py
    empty_label_init: "Select a type first",
    empty_label_selected: "--- Please select ---",
    disable_child: true
});