so I play jax top lane in blind pick, and I notice whenever I go up against a darius they will destroy me post six. How do I deal with a darius as jax?

Huge part of Darius's damage comes from his bloodstack. What you want to do is to perfect counterstrike his autoattack + cripple combo so that you don't get instantly push to 3 bloodstack.

You also outscale Darius hardcore.

Try to beat him before lvl 6. If you allow him to farm up he will beat you after 6

ok, thanks

literally to beat darius with jax is wait for him to use E to initiate on you and then trade him with E up and run away after the stun. Early on darius will push so he's very easy to gank even with amumu double buff it's almost 100% guaranteed kill. I like to build dorans shield on jax, like two and ninja tabi and you can just out trade him hard

Getting your jungler to gank unsuspecting, cocky darius players will also be a massive boon.

You're Jax. You don't lose to no one when you trade.

Pack a potion, be sure to strike only when you can pull your big combo (i.e. all your normal spells are up, including CS as above posters said). Sure, you can't simply 1shot people like the Jax of olden times, but you still come pretty close. Anyone who thinks he can outdamage you is going to regret that illusion very quickly.

If Darius troubles you a lot, ask your jungler to try to set-up a gank. Dyrus played Darius in the Season 2 Championship and lost his lane because the enemy had his jungler gank Dyrus numerous times. Learn to farm under your tower, don't fight irrationally unless you are confident that you can actually beat Darius. Always ask for ganks, if possible. Build to counter Darius while still thinking of the enemy's team composition.