I have created some custom fields for the WooCommerce Product CPT and I have set those fields to "Required". I want to apply this same functionality to some of the default WooCommerce Product fields on the admin side. I do not want users to be able to publish a product post or even to save a draft of it except that they are prompted to fill in the empty required fields.
Is Metabox using JQuery for this functionality or is it done via PHP?
Regarding the Required field setting, Meta Box adds the required attribute to the HTML input tag. It is validated by the browser. For example: <input type="text" required="1" id="text_4cjqazxdoup" class="rwmb-text" name="text_4cjqazxdoup" aria-labelledby="text_4cjqazxdoup-label">
Regarding WooCommerce fields, please contact WooCommerce support and ask them how to add the required setting to their fields.