Answer validation

Validation restricts what counts as an acceptable answer for Text Input questions and for individual Form Field fields. It runs twice with identical rules, instantly in the browser as the participant finishes a field, and authoritatively on the server when the page is submitted, so a participant can never bypass it and never sees two different opinions about the same value.

Kinds

• Email address. Accepts standard addresses and rejects close misses such as a missing top-level domain.
• Phone number. Accepts digits with common punctuation (plus sign, parentheses, dashes, dots, spaces), requiring a plausible number of digits.
• Number. Accepts numeric input, with optional minimum and maximum bounds configured on the question.
• URL. Accepts web addresses with a real host.

Configuring it

On a Text Input question, pick the validation kind in the question's settings, for Number, the bounds fields appear beside it. On a Form Field question, each field's kind doubles as its validation, an email field validates as email, a phone field as phone, a number field as number.

Changes save automatically, appear in the undo history, and work with redo like every other edit.

What participants see

Invalid values show a short, plain message under the field (for example, Please enter a valid email address) without browser-native popup bubbles, and the page scrolls to the first problem. The same message set appears whether the catch happened client-side or server-side.