With strict mode enabled, users are not allowed to provide some reserved keywords as values for form inputs.
Aside from the default words, you are allowed to provide a custom set of words to check against, please refer to the documentation.
Try to provide null, NaN or undefined as a value, then submit.
With strict mode enabled, extra white space at the start and at the end of an input value is removed.
With the callback feature, you can declare a function that will be invoked if validation tests passes or fails, then pass it as an argument to the validateCallBack() method.
Learn more about the callback method
Invoke this method anytime to see the number of validation errors on the form.
With the callback and status methods, you can alert the user in real time of the number of validation errors on the form.