How does it work?
When you visit a location-aware website in Firefox, the browser will ask you if you want to share your location.
If you consent, Firefox gathers information about nearby wireless access points and your computer’s IP address, and will get an estimate of your location by sending this information to Google Location Services (the default geolocation service in Firefox). That location estimate is then shared with the requesting website. (Source)
How accurate are the locations?
Accuracy varies greatly from location to location. In some places, the geolocation service providers may be able to provide a location to within a few meters. However, in other areas it might be much more than that. All locations are to be considered estimates as there is no guarantee on the accuracy of the locations provided. (Source)
In my case, Firefox reports that I am about 10km away from my real location.
How do I use this feature in my website?
You would do something like this:
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(function(position) {
alert(position.coords.latitude + ", " + position.coords.longitude);
// Use the latitude and location as you wish. You may set a marker
// on Google Maps, for example.
});
}
else {
alert("Geolocation services are not supported by your browser.");
}
You can see an online demo here: Firefox HTML 5 Geolocation Demo (Requires a geolocation-aware browser such as Firefox 3.1b3.)