Minimum and maximum character limit (conditional) for custom fields

Hi,

I would like to see a conditional minimum and maximum character limit for custom fields, e.g. we have a field which can be filled in by an end user, we call it 'Complaint Detail', I would like to add conditions to this to ensure someone write a minimum of 100 characters, maximum 1000.

We need data entry to be accurate on forms but at the moment the system allows anything to satisfy a mandatory field, we either get one-word entries such as 'problem', or someone writes an essay.

This mostly applies to multi-line fields but could apply to all.

The conditional setting needs to be native and shouldn't be difficult to implement.

Hope this makes sense?