Geolocation: watchPosition() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The Geolocation
method watchPosition()
method 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.
Syntax
js
watchPosition(success)
watchPosition(success, error)
watchPosition(success, error, options)
Parameters
success
-
A callback function that takes a
GeolocationPosition
object as an input parameter. error
Optional-
An optional callback function that takes a
GeolocationPositionError
object as an input parameter. options
Optional-
An optional object that provides configuration options for the location watch. See
Geolocation.getCurrentPosition()
for more details on possible options.
Return value
An integer ID that identifies the registered handler.
The ID can be passed to the Geolocation.clearWatch()
to unregister the handler.
Examples
js
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);
Specifications
Specification |
---|
Geolocation API # watchposition-method |
Browser compatibility
BCD tables only load in the browser
See also
- Using the Geolocation API
-
The interface it belongs to,
Geolocation
, and the way to access it —Navigator.geolocation
. - The opposite operation:
Geolocation.clearWatch()
- A similar method:
Geolocation.getCurrentPosition()