I would like the ability to create a membership database field that a logged-in member can only view from a Wild Apricot restricted webpage using the API from JavaScript.

Only an administrator with Full or Membership manager access would be able to view or edit this field. The Member would not have the ability to edit this field.

I would use the User ID but this is visible to other members in the profile URL (https://myorganization.wildapricot.org/Sys/PublicProfile/<User ID>/#######). This is the case even if the User ID is set to no access.