Home Forums ACF PRO 2 select parent the child taxonomy acf Reply To: 2 select parent the child taxonomy acf

  • Here’s an example of how we solved this problem:

    1. Pass Selected Parent Terms In AJAX
    You need a JS hook to filter the AJAX request of the child field, and add a new argument that contains the chosen parent term(s):

    add_action('acf/input/admin_footer', 'support_acf_152814_filter_child_ajax');
    function support_acf_152814_filter_child_ajax()
        global $post;
        //areas where this functionality is needed
        if (!$post || !isset($post->ID) || get_post_type($post->ID) != 'my_posy_type')
        <script type="text/javascript">
    $(document).ready( function() {
        acf.add_filter('select2_ajax_data', function( data, args, $input, field, instance ){
            let parent_field_key = '<parent_field_key>'; // Parent Field
            let target_field_key = '<child_field_key>'; // Child Field
            if( data.field_key == target_field_key ){
                let parent = acf.getField(parent_field_key);
                if (parent) {
                    data['parent_terms'] = parent.val(); //This is an array if the parent field is multiselect
              return data;

    2. Filter Taxonomy Query of the Child Terms
    Here, you need to catch the argument we introduced above, and modify the query accordingly.
    What I do here, is that I get the ids of all children of the selected parents, and I use put them in the ‘include’ option of the terms query:

    add_filter('acf/fields/taxonomy/query/key=child_field_key', 'support_acf_152814_child_terms_filter', 10, 3);
    function support_acf_152814_child_terms_filter( $args, $field, $post_id ) {
        // Check if this is an ajax call
        $children_ids = [];
    	if (wp_doing_ajax()) {
    		if (isset($_POST['parent_terms'])) {
    			$parent_terms = $_POST['parent_terms'];
                if (is_array($parent_terms) && !empty($parent_terms)) {
                    foreach ($parent_terms as $parent_id) {
                        $new_children = get_term_children($parent_id, 'disease_categories');
                        if (!is_wp_error( $new_children )) {
                            $children_ids = array_merge($children_ids, $new_children);
                $args['include'] = $children_ids;
        return $args;

    I tested the code above and it works in my case. Please @hube2 let me know if this can be improved further.