How do set my iphone 5s to shut off cellular data automatically, when Wi-Fi is detected?

How do set my iphone 5s to shut off cellular data automatically, when Wi-Fi is detected?

There's no any way to shut off it automatically dude.
You have to shut it off manually.

It does that already. When Wi-Fi is in range it switches to that & when it drops then it switches back to the data connection. Been that way since day 1 of the iPhone.