The Radio type means that the user can only select one
checkbox at one time; clicking on another causes the existing one to
become unchecked.
RADIO buttons are similar to CHECKBOXES,
but only one option may be chosen among many.
Specifies the value of the option to be sent to the server.
If not defined, a value of "on" is sent to the server.
CHECKED
This tag specifies which radiobutton to be selected by default.
Since it is implied that a selection will be made, it is best
to provide a default selection.
RADIO buttons are not good for lists with many items,
because the browser has trouble displaying a lot of buttons.
It would be best to use a SELECT menu element.
Once a radiobutton is selected, it cannot be deselected
without choosing a radiobutton with the same NAME.
The default selection can be restored with the use of the
RESET button.
If you have a bunch of RADIO buttons with the same
NAME and no VALUES specified, the server
won't be able to tell which is selected, since a default value of
"on" will be sent.