Does BreezingForms support a specific class or attribute to enable browser validation? For example validation classes of Joomla! (class="inputbox validate-numeric required" required="required").
Only on click on this submit button field is required, and if user doesn't fill it there will be error message.
Using submit button in breezingforms, will not affect fields which you add in section (that is the reason why I suggest to add submit button as html in section).
This submit button will only affect fields which you add as elements in forms.