How Do We Calculate Lifesteal?

When I see a weapon in Wynn it sometimes has the lifesteal attribute. (Duh.) This, naturally, allows you to steal health from mobs. (DUH.) What I'm not sure, however, is how you interpret the fraction on there, for example 2/4s lifesteal or whatever.

 

I think it means health stolen/per 4 seconds, but I'm not entirely sure.

 

It was supposed to, but it doesn't anymore. It and mana steal were changed. Basically there is a percentage chance the steal will occur on every hit, and it should happen an average of every four seconds. But it is a chance per hit, so it can happen more or less. The /4 is basically meaningless.
Also, the attack speed is not relevant, the chance decreases the faster you hit, so it still averages every four seconds.

 

Okay, thanks!