I am planning to create a field type to use as hidden captcha: a field that is hidden to users using a browser with enabled CSS, used to verify if the user registration is not done by a human being. I though to derive its widget from the
StringTextAreaWidget class, but I noticed that
StringTextareaWidget::formElement() uses two CSS classes: js-text-full and text-full.
What do those CSS classes do?
I would like the widget to be very similar to the textarea used to enter a long string, except that a CSS class I add would make it invisible. I would not want that the existing CSS classes would interfere in some way.
Alternatively, is there another class I should use? I see there is a
TextareaWidget class, but it seems for text with an input format associated, while I would need just plain text, without any input format associated.