Is it ok to leave iphone (4s) in charger after it is 100% charged?

I have a new iPhone 4s. I charged it for the first time after I had the battery completely empty. It took little bit less than 2 hours. But I left it for 3 hours more. Would that hurt the battery? Is it normal that it just took 2 hours for the first time?

It will not hurt the battery at all.
The battery will take the charge that it needs, & no more…

Its fine, honestly I do it all the time, but to me maybe its just me the battery seems to last a little longer.