Is it okay to let your iPhone to charge for a night?

I'm scared if I overcharged it, it would effect the battery life

I charge mine over night every night and I don't notice any difference.

It's fine, just don't leave it on for more than 36 hours, which will cause the battery to eventually burn.

The battery life will slowly get worse with time. By charging it for an entire night, it will not effect the battery life. It will slowly deteriorate with use regardless of excessive charging.

It's fine if you charge it all night. I did that for two years with my last android phone, and I do the same with my iphone, so I believe it will be okay.

Lithium batteries need to be discharged to about 10% left then you can charge them overnight, there's a limiter in chargers that stops charging when done. All good chargers do this and the iPhone has to have a good charger for that money. Just don't keep charging it before it gets down to 10% or the battery life will lessen. I've had that happen on my XM radio and GPS and they don't hold a charge anymore. Also iPhone batteries are soldered in so hard to replace. I've read this somewhere.

Apple products don't overcharge.

It would be fine.