Form field
From Joomla! Documentation
Form fields are fields in a HTML <form>. Joomla! 1.6
and newer supply the JForm class to conveniently and flexibly create forms with a large amount of form fields. Each form field type is a subclass of JFormField.
In addition to being a flexible page creation tool, JFormFields are used by Joomla! to allow administrators to configure Joomla! or its extensions without changing the underlying code. In Joomla! 1.5, this was handled by the now deprecated JParameter and JElement classes.