Advanced Validation
Some fields allow you to apply advanced validation for when certain data is inputted into the field
When on the field settings you will see a tab called advanced validation

In the "choose" drop down you will see various options
- UK Phone Number (Numeric, 11 digits)
- UK Postcode (Use regex rules to determine validation - google "Postcode Regex" for more info)
- SA Postcode(Use regex rules to determine validation - google "Postcode Regex" for more info)
- Credit Card(Use regex rules to determine validation - google "Credit Card Regex" for more info)
- Email (Uses an @ symbol with at least one full stop)
- Current Pattern (Leaves the current selection instead of changing to one of the above)
If for example, you use the UK Postcode option, the user on a script wont be able to navigate away from the page unless they input a valid (one that matches off the advanced validation) postcode.
You can also set your own validation, so again a bit of research into whatever you want to validate, chances are you can find a regex expression to accommodate online.