Ad Janna is ONLY MEANT FOR TOP. Doing good as Jana is very hard, the first 20 minutes or so is avoid taking damage, CS, and Harass when your shield is up. Also when laning in the beginning ask for several ganks for lane success. Also when playing Janna top *REMEMBER* she is squishy you may have to keep up wards constantly!

• Greater Quintessence of Critical Damage: // Maximizing damage
  
• Greater Mark of Critical Damage: // Maximizing damage
  
• Greater Glyph of Critical Damage: // A bit of extra health to help you late game
  
• greater seal of Vitality: // Maximizing damage

For Seals I recommend health per level because early game you don't need health because of your shield. For your Glyphs, Marks, and Quintessences I suggest critical damage to optimize the damage, 100% critical chance, and your shield.

• : // Phantom dancer will definitely give you the attack speed, MS, and critical you need. It is a nice items that goes a long with your shield very well
  
• : // burst Only get this if you are having trouble staying alive and you need to survive burst damage of AP champions.
  
• : // Gives you great damage more crit chance and along with your runes should help you with big crits.
  
• : // Janna is very squishy lifesteal is what helps you survive plus it gives you tons of Damage.
  
• : // A Second one is not essential but getting more lifesteal for vrsing people who have and also with 2 of them you can solo baron : )
  
• : // Same use as the first just getting closer to 100% critical strike!
  
• : // I love this item on any AD carry it always seems to help you get a slow, some hp, MS, Crit strike, atk speed, and a big amount damage after casting a spell followed up with your shield = very good damage!

As for the start of the game Boots of Speed is a very good choice for the beginning movement speed and the price. The reason its a smart choice: you have money for Sight Wards or Health Potions depending on their jungle or top solo, you can easily get away run away from danger, and it allows you to get a creep kill or harass and get out fast. After that you want to build some more AS and MS by getting Zeal and finishing off the Berserker's Greaves. This will allow easier CS, better get away, and harass. After you finish Phantom Dancer You will now be on your way to get your damage grab a B.F. sword and depending on whether you need survivability or more damage grab Infinity's Edge or Bloodthirster. Once you get Both of those items sell your boots and choose from 4 items and get 3 of them in the order they will help you Warmog's Armor, Trinity Force, a 2nd Phantom Dancer, and a 2nd Bloodthirster.

[Flash]: // Good for securing your kills and getting away from tough spots almost every champ needs this spell.
[Exhaust]: // This spell is great for AD Janna because it helps with ganks, reduces enemy champs damage, and can almost guarantee kills. Also is a good way to surprise the enemy into thinking that sense your Janna there is no way you can kill them and even with exhaust.

spaaaaaaace

Pros + // absorbs damage + // Also gives good damage + // has several get away spells + // Aoe heal that also knocks back + // Hard to gank + // Fun to play

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Cons - // Extremely squishy - // Bad against other range heroes early game - // Damage from shield goes away after max damage is absorbed - // People won't let you top because they say its not possible - // Incredibly low stats in the beginning - // Without proper CS and feed you are a useless champ

All in all Janna is actually a viable AD champ although she must be used right. She can run in quick rape a couple of people then run out without a touch. I would say my favorite part of AD Janna is proving people it actually works. I thank all of you for reading this plz vote and leave comments on what you think about it. ( I soloed baron with her)

Credits to jhoijhoi for the template, which you can find here.