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---
geolocation.watchPosition
=========================
Watches for changes to the device's current position.
var watchId = navigator.geolocation.watchPosition(geolocationSuccess,
[geolocationError],
[geolocationOptions]);
Parameters
----------
- __geolocationSuccess__: The callback that is called with the current position.
- __geolocationError__: (Optional) The callback that is called if there was an error.
- __geolocationOptions__: (Optional) The geolocation options.
Returns
-------
- __String__: returns a watch id that references the watch position interval. The watch id should be used with `geolocation.clearWatch` to stop watching for changes in position.
Description
-----------
`geolocation.watchPosition` is an asynchronous function. It returns the device's current position when a change in position has been detected. When the device has retrieved a new location, the `geolocationSuccess` callback is invoked with a `Position` object as the parameter. If there is an error, the `geolocationError` callback is invoked with a `PositionError` object.
Supported Platforms
-------------------
- Android
- BlackBerry WebWorks (OS 5.0 and higher)
- iOS
- Windows Phone 7 and 8
- Bada 1.2 & 2.x
- webOS
- Tizen
- Windows 8
Quick Example
-------------
// onSuccess Callback
// This method accepts a `Position` object, which contains
// the current GPS coordinates
//
function onSuccess(position) {
var element = document.getElementById('geolocation');
element.innerHTML = 'Latitude: ' + position.coords.latitude + '
' +
'Longitude: ' + position.coords.longitude + '
' +
'
' + element.innerHTML;
}
// onError Callback receives a PositionError object
//
function onError(error) {
alert('code: ' + error.code + '\n' +
'message: ' + error.message + '\n');
}
// Options: throw an error if no update is received every 30 seconds.
//
var watchID = navigator.geolocation.watchPosition(onSuccess, onError, { timeout: 30000 });
Full Example
------------
Device Properties Example
Watching geolocation...