A port of the Geolocation example used in the [A Simple Trip Meter Using the Geolocation API] (http://www.html5rocks.com/en/tutorials/geolocation/trip_meter/) article by Michael Mahemoff, originally published on HTML5Rocks.
The Geolocation API lets you track a user's location. The API is device-agnostic; the underlying mechanism might be via GPS, wifi, or simply asking the user to enter their location manually. Since these lookups can take some time, the API is asynchronous, and you pass it a callback method whenever you request a location.
The Trip Meter example display's the user's initial location, and it tracks the distance the user has travelled since the page was loaded.
Please report any bugs or feature requests.