Which means that if they join the snap leaderboard, they can't choose to post to a javascript leaderboard.
wow. lol. but as I and ego-lay_atman-bay have said, you cant post to a specific leaderboard.
Oh. I get it. Well, then, I don't have a solution, except maybe that people who use JS should flag their submission somehow.
and if your code works properly, that shouldn't matter