
I get it!
Anyways, I found a question on Quora.com in which the author asked the same question. According to answerer Rufo Sanchez, when your iPhone is connected to a wireless router that is not connected to the Internet, your iPhone will use your cellular data connection. The phone will allow any program, including Webpages, to send data to and receive data from any wireless device that is connected to the same WiFi network.