Im going to skip the **** and get down to it. This build probably wont work in high elo but if your in bronze, silver maby even gold this build is the easiest way to carry with jax. Early game you just need to focus on farm because you wont be very strong. Once you get your 3 daggers you can go aggresive, but if you enemy top laner wants to farm i would just farm because there are few champions that scale better into the mid/late game than jax. Once you get your 3 daggers and tiamate you should be able to clear a wave in under 10 auto attacks. After that you should get your choice of boots. Go beserkers if your going to have to carry and Merc treads if your going to be acting as a normal tank/fighter. After that i like to finish Blade of the ruined king for increased kill potential and then finish your hydra to the biggest threat in a team fight. After that you will need a frozen mallet to stick to people in team fights to keep your lifesteal going. If your team lacks CC get a frozen gauntlet ontop of the mallet to get constant CC/Damage machine. If your team dosent need the cc then go Trifroce because it will increase your damage more than any other item. But increasing your damage your increasing your survivrability in team fights and duels. If the enemy Top laner is doing well or there jungler is becomming a proplem you should get a Black cleaver. This item works In this build because of your uber fast attack speed. But if the enemy top laner/jungler is doing normally well then you should just get a Triforce.

BTW make sure you have at least 2 HP items to keep the Enemy From bursting you down instantly.