anchor.diff:            value: form.object.date_of_birth.try(:year),
             placeholder: 'YYYY',
             class: 'form-dob__input form-dob__input--year js-dob-year t-date-of-birth-year',
  -          pattern: '(19)[0-9]{2}',
  +          pattern: '[0-9]+',
             maxlength: 4,
             title: 'Must be numeric eg 1955',
             required: true
  
positive.code:           value: form.object.date_of_birth.try(:month),
            placeholder: 'MM',
            class: 'form-dob__input js-dob-month t-date-of-birth-month',
            pattern: '(0?[1-9]|1[0-2])',
            maxlength: 2,
            title: 'Must be numeric eg 01',
            required: true
  
negative.code:           value: form.object.date_of_birth.try(:day),
            placeholder: 'DD',
            class: 'form-dob__input js-dob-day t-date-of-birth-day',
            pattern: '[0-9]+',
            maxlength: 2,
            required: true,
            title: 'Must be numeric eg 01',
  