The Behavior Pane
In the behavior pane you can set input validation for any Text Box or Text Area element in your form. Input validation lets you check what value a user has entered in a form field against various criteria and not allow your form to be submitted until the input satisfies that criteria.
The criteria you set are called 'validation types' and formArchitect has several default validation types like requiring the field be filled in and checking if the value is an email address. You can also define your own custom validation types (using regular expressions).
Javascript Required
Javascript is used to implement input validation so a form user must have javascript enabled in their browser for input validation to work. Also, bypassing javascript validation is fairly easily done so you should not rely solely on the validation you set here to verify user input.
You should always provide input validation in your form processing script in addition to setting validation here.