The W3C Geolocation API specification merely defines an interface by which we can obtain data. Where and how geolocation data arrives is rather an implementation detail. On most mobile devices, GPS is usually built in and is gathered through a combination of satellite data, WiFi, and GSM/CDMA cell tower location. On desktop devices, Wi-Fi and geolocation based on IP address can be used. Lastly, Google offers a geolocation service fueled by its StreetView data. Needless to say, what goes on under the hood need not worry us, but it is good to understand how the magic really happens
The following are the supported browser:
Firefox 3.5+
Chrome 5.0+
Safari 5.0+
Opera 10.60+
Internet Explorer 9.0+
Support is rendered on the following mobile devices:
Android 2.0+
iPhone 3.0+
Opera Mobile 10.1+
Blackberry OS 6