There are times you would want to show only fields that only appears after selecting a required parent term. For example, you may need to select a child term that only appears as a selection and becomes available only after selecting its corresponding parent taxonomy term. For instance, you need to select Country first, only then will the States of that country will appear as a selection.
To do this, you will need to download and install the Conditional Field module https://www.drupal.org/project/conditional_fields. The module/project page describes its use case:
Conditional Fields allows you to manage sets of dependencies between fields. When a field is “dependent”, it will only be available for editing and displayed if the state of the “dependee” field matches the right condition. When editing a node (or any other entity type that supports fields, like users and categories), the dependent fields are dynamically modified with the States API. A simple use case would be defining a custom “Article teaser” field that is shown only if a “Has teaser” checkbox is checked, but much more complex options are available.
As an example, we have a Content Type called Organizations which will serve as content items for different purposes and will be categorized for example as Partners and Distributors. Under Partners for example, we have to further categorize each to a sub-classification such as Philippines, or Other Countries. To set this up and use this in Drupal 8:
- Download, install and enable. Follow the steps in installing modules here – https://www.drupal.org/docs/8/extending-drupal-8/installing-drupal-8-modules
