Number fields allow text input

Bug Reports
1

Steps to Reproduce:

  1. Go to https://sffform.2sinn.biz.
  2. In the “Antragsteller” section, fill the fields, “Institution” and “E-Mail-Adresse”.
  3. Scroll to bottom and click “Weiter zu Kosten” button
  4. Type some text into any of the “Betrag (€)” fields

Shouldn’t the number fields not permit text input?