7.4 upgrade to Tim Geyssens Char Limit package.
This is a very basic package, it’s just a new datatype (Char limit 7.4), a textarea with a limit on the characters.
The character limit can be set on the edit datatype page.
So you get feedback on the amount of characters left when you are typing and it will stop characters exceeding the limit.
All code available in App_Plugins/TextAreaCharacterLimit