Fix file to stop web devoloper from editing html

Not hiring no-one over my pay of $10.00 at end of project, i create milestones at end of completion...I will only hire people who can do this with files alone... On my register page i need to change something to block people from tampering and using web developer and changing the input max character allowed etc. etc. Some people are abusing web developer ...I tested it and they edit html on developer and overwrite my input code.. Need to fix this from happening. Similar to what facebook uses to block them from editing the html. NOT giving C/panel logins nor FTP,,, ONLY the file needed, i will share site logins for testing...