In addition to getting the user position once, which you can do using getCurrentPosition(), you can use the watchPosition() method of navigator.geolocation to register a callback function that will be called upon each and every change that the device will communicate to us.

Usage:

navigator.geolocation.watchPosition(position => {
  console.log(position)
})

The browser will ask for the permission also with this method, if it was not already granted.

We can stop watching for a position by calling the navigator.geolocation.clearWatch() method, passing it the id returned by watchPosition():

const id = navigator.geolocation.watchPosition(position => {
  console.log(position)
})

//stop watching after 10 seconds
setTimeout(() => {
  navigator.geolocation.clearWatch(id)
}, 10 * 1000)

Lessons in this unit:

0:	Introduction
1:	Getting the user's position
2:	▶︎ Watching the position for changes
3:	If the user denies the position
4:	Adding more options