Jax, Jaximus the gladiator is a fun champin. For one to be able to really dominate the ring with jax, one must firt understand the concept of hybrid fighting and adjust you play and gear to counter your opponents. That why the item build above is just a basic option, that can counter most opponents but might not be the top most super best build for every type of enemy team. This build focusses on countering Armor and hp tanks and other Ad fighters, which are in general the most and the strongest opponents you will face in dominion.

PS. Mobafire does not calculate the passive in his health. you will have about 4000 Health on level 18 with this build, depending on your choice of items.

I am sorry to inform you that there is NO viable good or informing video on youtube about jax. It is just a few bad people showing off their only good game against very stupid opponents with the most dumb builds ever. If any of you feel obliged to answer this call, than please do so: we need a good champion spotlight of jax!

Here is a short movie about the usage of jax. He dives in, nukes and gets out. It is no spotlight, nor will it be of much use to you, but at least you can see all his spells at work in it:

Play Video
He uses Q to dive in, W to hit with extra damage, his E stuns around him and does some more damage and his ult is used passivly, but could be activated to reduce incoming magic damage (useless against xin and ash)

Jax builds upon a combination of AD, AP and attack speed. AD could be taken as well, but most tanks and hybrid fighter/tanks usually build more armor than magic resist, so always keep in mind that ap is often the better option. Hence the runes focus on both attack speed and magic damage.

The attack tree obviously boosts jax damage nicely and the defensive skills dodge + move speed after dodge combine really well with jax. He gets extra dodge and it is often a good idea to take ninja tabi, so the 21/9/0 is really the best option for you.

Here comes the tricky part. Jax first items should be ninja tabi and Hextech gunblade. These combine well with all his spells and give you maxed out early game damage.

Once these are in the pocket, the rageblade is a good option. One small advantage of this thing is extra damage while killing minions as well higher damage output during long fights. A downside on this item is the build up it needs, making it a lesser item when you want to dash in and run again. Still it is not that expensive and in the long run, it is a good option.

Now the tricky part, do we go for AP, for AD or full hybrid? For this you need to check your opponents as well as your teammates items and kills. Does your team have heavy ad and is the opponent building armor? Take Rabadons deathcap. Does your team have good AP? take infinity edge or sanguine blade.

Try to figure out wat flaws your team has and what it`s weak spots are. Do you have two AD characters but they are really messing up and your one mage, like heimerdinger, is doing great? you might want to take more AD than, so the enemy will not build Magic resist and render your only mage less useful.

Balance your items if your whole team is doing well, for this will give you maximum damage on any opponent.

Equipment Mastery
Jax's prowess with weapons and armor increase his fortitude as he gains equipment:
Jax gains 3 Health per point of Attack Damage received from items.
Jax gains 2 Health per point of Ability Power received from items.
passive

Leap Strike
Jax leaps toward a target. If it's an enemy, he hits the enemy for 50/75/100/125/150 (+) (+0.7) magic damage.
Cost 65 Mana
Range 700

Empower
Jax charges his weapon with energy, causing his next attack to deal an additional 75/110/145/180/215 (+) (+0.4) magic damage.
Cost 20 Mana
Range 300

Counter Strike
Jax's prowess allows him to dodge enemy attacks frequently. After avoiding an attack Jax can quickly stun surrounding enemies.

Passive: Increases Jax's Dodge chance by 10/12/14/16/18%.

Active: Jax stuns surrounding enemies for 1/1/1/1/1 second and deals 80/110/140/170/200 (+0.6) magic damage to them.

Usable only within 7 seconds of dodging an attack.
Cost 60 Mana
Range 400

Relentless Assault
Jax's greatest talent lies in his ability to grow stronger with every attack. Each successive attack increases his Attack Speed temporarily, and every third blow will devastate his target. Jax can activate this ability to gain temporary Magic Resist based on his Dodge chance.

Passive: Jax's basic attacks increase his Attack Speed by 6/10/14% for 2.5 seconds (max 10 stacks = +60%/+100%/+140%). Every third consecutive attack deals 140/170/210 (+0.7) bonus magic damage.

Active: Jax's speed allows him to reduce incoming magic damage. For 5/6.5/8 seconds his Magic Resist is increased by 20/35/50 plus his Dodge percent totalling Magic Resist.
Cost 80 Mana

Balance your skills, they are all useful and combining them is key to be a strong jax.

Speed is of the essence, more for jax than for any other champion. Ghost and flash give him great map control.

Make sure you take out the weakest opponents first. Jax can jump on anybody in teamfights and ranged always go down the fastest. You might want to considder taking down their best damager first too, jax can. Try to stay in team with other champions and try to initiate whenever you can. Hit and run is a great tactic, as well as just plain old face-checking melee combat.

One thing you want to try to avoid is fighting at an enemy point. Again keep harassing untill the enemy is below 50% hp, than try to finish them off. Also keep in mind that each third hit deals extra damage, so trying to get this hit to be the first hit is also a way to guarantee extra damage in your nuke-dive.

One extra tip, before you go smashing enemy heads into bits: Minions can proc your E, before engaging an enemy, it might be smart to *get hit* by enemy minions, wait for your E to proc and than start to fight. The stun it will give you often makes the difference between killing the champion and seeing him flash and ghost out of range, or back under their point.