New pseudo-classes:

:default      Such as default selection in a menu
:valid        Data value is valid (XForms)
:invalid      Data value is invalid (XForms)
:in-range     Data value is in range (XForms)
:out-of-range Data value is out of range (XForms)
:required     A form element that is required
:optional     A form element that is optional
:read-only    A form element that can be altered
:read-write   A form element that can be written into