Single checkbox

Generate a checkbox which is checked by default:

['var' => 'mycheckbox', 'label' => 'Check this!', 'type' => self::TYPE_CHECKBOX, 'initvalue' => 1],

This checkbox is unchecked by default:

['var' => 'mycheckbox', 'label' => 'Check this!', 'type' => self::TYPE_CHECKBOX],

which is equals to:

['var' => 'mycheckbox', 'label' => 'Check this!', 'type' => self::TYPE_CHECKBOX, 'initvalue' => 0],