Hey @KrnA! Thanks for posting in our community! I’d like to share a custom form field validation script thread that we have here in our community! You may need to work on the regex but I think that this would fit your use case or at least help point you in the right direction. I will share it below:

• Custom Form Field Validation

I hope this helps @KrnA, if you do need additional assistance after reviewing the script on the page then please feel free to reach out in that thread and hopefully a community member can provide some further insight for you! I hope you have a great day ahead @KrnA!