You may have the same fields within a form that use different id or name attributes based on an end-user or a setting. You can track these dynamic fields as one field by assigning the attribute nls_fa_el_name to these, using the same name/identifier for each field.
The nls_fa_el_name attribute does not work for non-input elements. It works only for the <input>, <select>, and <textarea> tags.
NOTE: Custom field elements are not tracked by default. However, VWO provides API to help you in tracking custom fields. To know more, please write to us at support@vwo.com.