Jax is a champion that is pretty strong mid to late game,with that being said you should play passive on early levels and wait for about two items most players will get triforce + hextech gunblade and will then you will be able to 1v1 everyone.
At level 1 you have a pretty good trade vs almost every melee champion in the game cause of your third spell
A spell that every champion needs either to get away from a situation or make a play
Teleport has become the must spell for every top lane champions,not only it will keep you in the same levels as your enemy player in the lane,but you can also teleport almost everywhere in the map and start a teamfight or help another lane.
Almost no one takes Ignite at high elos,but it is pretty useful at those 1v1 situations where it will become pretty useful,a good choise but not worth taking because you will stay behind in the game and at the levels