Registration form: it's impossible to provide the DoB from a mobile phone

I tried to fill in an Indico registration form with the CERN site access section (place and date of birth etc.). Unfortunately, it's impossible to type in the date of birth (DoB) from an iPhone (tried with both Safari and Chrome). It's perhaps possible to select the date by hand in the pop-up calendar, but I'd first need to tap "previous month" many(!!) times to get back to the month of my birth - effectively making it very hard or almost impossible.

Reproduce the CERN site access registration form on an iPhone using Safari and Chrome, focusing on the date-of-birth field. Trace the form code responsible for the mobile date input or calendar, then verify that a user can enter an earlier birth date without repeatedly tapping the previous-month control.

Written by the indexing model from the issue text.