Embed code: how to write a validation message?

Thank you… but the issue is:

suppose that theuser write 7 characters in a field and the validation rule is “do not write more than 5 characters” .I want to inform the user that he must write max 5 characters.

Which is the jquery instruction to write the info “please write maxt 5 characters”

in the same area of the screen where usually hubspot write his own messages? (just below the input field as show in image of my t post)

Thank you