How do you detect 3G vs. Wifi connection on mobile safari?

Question

I am specifically asking about javascript on a mobile webpage, not an objective-c application. Is there something like Apple Reachability for javascript so I can tell when Edge,

Answer 1

Although you cannot use data from a browser to detect if the user is on Wifi or a cellular connection - capturing the user's IP may be one way to differentiate between a Wifi and Cellular connection.

In this article about how cellular impacts your IP address (http://classroom.synonym.com/wifi-change-ip-17586.html) it states the following:

While on Wi-Fi, your device's public IP will match all other computers on your network, and your router assigns a local IP. While using a cellular connection, your cell carrier assigns a public IP. Connecting to the cellular Internet does not use a router, so your device won't have a local IP.

IF ip = localIp, then connection = wifiConnection

IF ip = publicIp, then connection = cellularConnection

Here's a screenshot of my IP when I'm on cellular:

Here's a screenshot of my IP (right after turning off cellular) on Wifi:

This could be one answer to the problem without browser help.