Unless otherwise specified you can always specify the message option to customize the message returned if the validator doesn't pass.
It does little more than proxying the call do the main validation function but with the value wrapped in an object and the options full Messages and format set to also has limited support for nested objects (objects within objects) using the dot notation.
They are meant to give a feeling for how to use the library and should not be considered production ready code.
The native HTML form validate has been disabled in a demo purpose so that you may see how works in action.
It is unit tested with 100% code coverage and can be considered fit for production.