This is script not a form
After installation, go to your message box->Properties->Validation->check Library->and find this script (ff_avoidLinks).
Let me know if you need more help
I have downloaded and installed that avoidLinks package, but I am not getting the expected results. Also, if the field is required, but nothing is filled in, there is no validation. How to combine the ff_valuenotempty with the ff_avoidlinks?