Т.е. для одних полей можно делать AJAX валидацию (например, капча или логин), для других генерировать простой JS.The AJAX-based validation and client-side validation may be used together or separately. For example, in a user registration form, one may use AJAX-based validation to check if the user has picked a unique username, and use client-side validation to ensure all required fields are entered with data. Because the AJAX-based validation may bring extra workload on the server, if possible, one should mainly use client-side validation.
Не могу понять, где это настраивается?