Returns HTML for the label for the empty value for options that are not required.
The default theme will display N/A for a radio list and '- None -' for a select.
$variables: An associative array containing:
function theme_options_none($variables) {
$instance = $variables['instance'];
$option = $variables['option'];
$output = '';
switch ($instance['widget']['type']) {
case 'options_buttons':
$output = t('N/A');
break;
case 'options_select':
$output = $option == 'option_none' ? t('- None -') : t('- Select a value -');
break;
}
return $output;
}