jokingly

What’s the ruling of people who said “I’m not a Muslim” jokingly? Does he have to renew his syahadah? How about those who says wrongly, but yet ignorant about Islam (i.e those who say that hijab is not obligatory for muslim women, but he didn’t really know what he’s talking about). What about those who make fun of Islam, but have no intention to get out from Islam? What  should they do?