HTML 5 location detector or Big Brother watches you

Internet brought me an interesting site SunCalc.net.
The site realization is interesting itself, but I would like to mention one really wonderful feature, used there.

On the site, click on Location input box. In pop-up window, click “Detect my location” button.
In Chrome, you will see the following bar message:

If you click on the “Learn more” link, you will get an explanation what it is and how to deal with it.
I got interested, how this feature was done.

Answer is very simple – Google Maps API v3 allows to detect your location from browser. Here is a detailed overview.

There are some interesting aspects, I would like to highlight:

  • According to Google Maps API doc, this is HTML5 specification feature, which simplifies user location detection without special devices. This is a pretty good news – make easy for user to set current location.
  • Location is detected from User side. And I don’t know how it works. My home internet connection was detected with 20-30 meters infelicity. This sounds a little creepy for me.
  • NAT firewall doesn’t save from location detection through your browser. Only streaked VPN connection settings can make you invisible for this type of location detection.