Geolocation: watchPosition() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Secure context: This feature is available only insecure contexts (HTTPS), in some or allsupporting browsers.

ThewatchPosition() method of theGeolocation interface is used to register a handler function that will be called automatically each time the position of the device changes.You can also, optionally, specify an error handling callback function.

Note that in addition to requiring a secure context this feature may be blocked by thegeolocationPermissions-Policy, and also requires that explicit permission be granted by the user.If required, the user will be prompted when this method is called.The permission state can be queried using thegeolocation user permission in thePermissions API.

Syntax

watchPosition(success)watchPosition(success, error)watchPosition(success, error, options)

Parameters

success: A callback function that takes aGeolocationPosition object as an input parameter.
errorOptional: An optional callback function that takes aGeolocationPositionError object as an input parameter.
optionsOptional: An optional object that provides configuration options for the location watch.SeeGeolocation.getCurrentPosition() for more details on possible options.

Return value

An integer ID that identifies the registered handler.The ID can be passed to theGeolocation.clearWatch() to unregister the handler.

Examples

let id;let target;let options;function success(pos) {  const crd = pos.coords;  if (target.latitude === crd.latitude && target.longitude === crd.longitude) {    console.log("Congratulations, you reached the target");    navigator.geolocation.clearWatch(id);  }}function error(err) {  console.error(`ERROR(${err.code}): ${err.message}`);}target = {  latitude: 0,  longitude: 0,};options = {  enableHighAccuracy: false,  timeout: 5000,  maximumAge: 0,};id = navigator.geolocation.watchPosition(success, error, options);