Dear Master of ZOHO

I ma completely new in scripts of ZOHO. Basics of programming I am familiar with but I can not solve it through web research and my skills today.

Field info

Field label: Telefon komórkowy

API name: Mobile

Field type: Phone

(if the field type must be change into string that is no problem)

Module name: PreLeads

I want to do by this script 2 things:

1) verification of data: 9 numbers

2) presenting those numbers with space in between each 3 digits: 888 888 888; 123 456 789;

Can you please share with me proper full code for copy/paste so that I can learn on it for further plans?

Thank yu warmly in advance,

Kochnik