Which kind of junk data do you mean? We have quite a few constraints based on fields, so a number field will only accept integers/decimals and it's validated ba

Which kind of junk data do you mean? We have quite a few constraints based on fields, so a number field will only accept integers/decimals and it's validated backend. We also have a regex system that is validated backend, so you can force user input for a particular field to conform to it. We're working on adding custom Javascript scripting partially for this purpose. The idea is to set scripts that will run at different parts of the submission process. For example, one script runs for the submission page and you can control the frontend. Another would run backend in sandboxed NodeJS with custom validation rules on each new submission.