[3.0.18] Registration form input minimum lenght

[YodaStudio]

Good morning everybody.

I added a custom field to new customer registration form. I'd like to have a verification on the text lenght since it must be exactly 13 characters long and this field is required.
I have no idea how to get it.

Any help?
Thanks.

[Studio 42]

You can use a Joomla system plugin and check for this, but this need a javascript too.
Or perhaps using a userfield plugin. but i dont think that Vm have specific length rules in core.

[YodaStudio]

I found no plugins that allow me to get what I need.
I guess I have to edit some code (including javascript) but I don't know what to do. That's the reason why I asked this community.

[Studio 42]

You are a developper, no ?
Check the field value and length and set it as required should not be a problem.