Disconnect to wifi when screen off

hykaru wrote:

My iPhone auto disconnected to wifi after few moment when I turn off screen, and auto connect when I tap to screen to wakeup. Is that normally?

Yes, iPhone is designed to disconnect from Wifi when the screen locks, unless you are doing something such as streaming music. This is to help save battery power when the phone is not being used. If you don't want Wifi to disconnect when the screen is locked, plug the phone in to charge and Wifi will not disconnect. Again, the behavior you are seeing is normal and expected and by design.

You may get better and prompt responses if you may kindly provide the iPhone Model that you have and the iOS version if it is known to you and re-post.

First of all how do you know it disconnects after few moment when the screen is off. Is it your perception?