This is a fantastic site. Great job, I've been waiting for something like this.
One thing I've noticed, I'm probably missing something obvious, but I'm not sure if attack speed is always being calculated properly or something.
Check the difference between these links (just to be extensive in case it's more than one item)
Nothing - +0%
-Lvl 18 attack speed = 0.819
Berserker's Greaves - +25% attack speed
- Lvl 18 attack speed = 1.276
Nashor's Tooth - +30% attack speed
- Lvl 18 attack speed = 1.246
Recurve Bow/Wit's End - +40% attack speed
- Lvl 18 attack speed = 1.185
I updated and refreshed these pages and it doesn't seem random, but those don't seem right to me.
Also, I have a couple of suggestions which I wasn't going to add in earlier because I didn't want to seem as if I only have criticism and suggestions for an already awesome site. Anyways, these are just ideas.
-Automatically calculate the total gold spent on the items bought
-Add the opposite of theoretical damage per second, the amount of damage you can take from full health against physical and/or magic attacks.
-Allow the dps calculations to be run on a "dummy" for instance your level "X" warwick with "X" items against a level "X" Dr. Mundo with "X" items. So you can see the effects of items/levels/defensive abilities/etc.
-Instead of turning every spell into an equation (because there is no way to calculate what Taric's, or Sion's R moves would do, or for another example Master Yi's abilities) allow us to add percentage increases to base damage, attack speed, etc to fabricate abilities that increase statistics. possibly add this to "defensive dummy" idea too.
I had a couple more, maybe ill think of them later. I know you got some work to do, but I hope these might help somewhat.