Geolocation

Basics

Geolocation is the art of figuring out where you are in the world and (optionally) sharing that information with people you trust. There is more than one way to figure out where you are — your IP address, your wireless network connection, which cell tower your phone is talking to, or dedicated GPS hardware that calculates latitude and longitude from information sent by satellites in the sky.

Geolocation API
The geolocation API lets you share your location with trusted web sites. The latitude and longitude are available to JavaScript on the page, which in turn can send it back to the remote web server and do fancy location-aware things like finding local businesses or showing your location on a map.

The geolocation API centers around a new property on the global navigator object: navigator.geolocation.

The simplest use of the geolocation API looks like this:

function get_location() {
  navigator.geolocation.getCurrentPosition(show_map);
}

That has no detection, no error handling, and no options. Your web application should probably include at least the first two of those.