Behavior and validation
These pages cover how the form checks input and what happens when someone clicks a button: validation rules, actions, events, error
messages, and modals.
In this section Validation basics Required fields, built-in rules, and Auto Validate: how validation works for form authors in Designer. Actions basics What form actions are, how buttons trigger them, and what form authors configure on the Actions tab. Form-level actions in Settings Create reusable Code actions and a form validator in Settings, then attach actions to component events. Events and actions concept What happens when users click or change fields: events trigger actions on buttons and forms. Action order on buttons Run validation before later button actions, and use failOnError when validation must stop the sequence. Common validation patterns Required, email, min/max length, and regex rules: pick from Add a validation rule and test messages in Preview. Custom error messages Write clear validation messages on the Rules tab so users know how to fix each field. Modals for form authors Build a confirmation modal form, link it from a main form with Modal and openModal, then open it from a button in Preview.
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