ANA/JAL Dress Code

Hello, Looking at taking a domestic flight on JAL/ANA next week and was wondering how strict they are on dress code? According to my airlines page on them jeans and sneakers are not allowed? Not looking to really pack one more set of clothes just to fly a short domestic segment. I was kinda hoping that it was a lot like most airlines with just no opened toed shoes and don't dress like a slob. Thanks.