How to validate field with brackets in name

@Ahmed Haroon i used the dot notation but misspelled the name of the input field in the showError() function. This was the reason why no error message was displayed

$validation->showError('button.10') shows me the correct error message

thanks for your feedback, this will help us for sure.

Newbie here in CodeIgniter World !! Please appologize if any nonsense from me.  

environment: Windows 10, XAMPP 3.3.0, VS Code, SQLyog Community Ed.