Talk:Jax/@comment-3578129-20140105205626/@comment-9848924-20140105220638

Spell Weaving procs on auto attacks, so it works with W and R (passive), because after all you are auto attacking.

Blade Weaving procs on "any ability that is not a passive ability or deals true damage. This includes any Empowered Attacks"  Jax' W is an Empowered Attack (got it?) and his 3.rd hit R is a passive ability.

tl;dr:

Spell Weaving: W and R

Blade Weaving: W, but not R