The good news is: I've done it... I've figured it out. The bad news is: somebody smarter than me is going to have to tell you why this works, whereas any other variation of this solution or any of the other solutions offered don't work. This was a hard-fought victory but I'm too embarrassed to say how many hours (days) it took me to figure this out. Without further ado:
if (window.navigator.geolocation) {
var accuracyThreshold = 100,
timeout = 10 * 1000,
watchID = navigator.geolocation.watchPosition(function(position) {
$('#latitude').val(position.coords.latitude); // set your latitude value here
$('#longitude').val(position.coords.longitude); // set your longitude value here
// if the returned distance accuracy is less than your pre-defined accuracy threshold,
// then clear the timeout below and also clear the watchPosition to prevent it from running continuously
position.coords.accuracy < accuracyThreshold && (clearTimeout(delayClear), navigator.geolocation.clearWatch(watchID))
}, function(error) {
// if it fails to get the return object (position), clear the timeout
// and cancel the watchPosition() to prevent it from running continuously
clearTimeout(delayClear);
navigator.geolocation.clearWatch(watchID);
// make the error message more human-readable friendly
var errMsg;
switch (error.code) {
case '0':
errMsg = 'Unknown Error';
break;
case '1':
errMsg = 'Location permission denied by user.';
break;
case '2':
errMsg = 'Position is not available';
break;
case '3':
errMsg = 'Request timeout';
break;
}
}, {
enableHighAccuracy: true,
timeout: timeout,
maximumAge: 0
}),
delayClear = setTimeout(function() {
navigator.geolocation.clearWatch(watchID);
}, timeout + 1E3); // make this setTimeout delay one second longer than your watchPosition() timeout
}
else {
throw new Error("Geolocation is not supported.");
}
Note: for some reason, this doesn't seem to work as consistently if the execution of this code it delayed at some point after initially launching the app. So, this is the FIRST thing I execute in my initialization method.
Note: The only other thing I've added to my app is, when I need to use the geolocation data (which, for me, takes place after the initialization of several other Classes/Object Literals), is to check for the latitude/longitude values. If they exist, continue; If not, run the above geolocation method again, then continue.
Note: One of the things that threw me for a long time was that I only needed to get the current position of the user. I didn't need to track the users' movements. I kept trying different iterations of this with the getCurrentPosition() method. For whatever reason, it doesn't work. So, this is the solution I came up with. Run it like you're going to track the users location (to get their location in the first place), then once you've gotten their location, clear the watchPosition ID to prevent it from tracking them. If you need to track their location as it changes over time, you can of course... not clear the watchPosition ID.
HTH. From everything I've been reading, there are a lot of developers who need this functionality to work for their mission-critical apps. If this solution doesn't work for you, I'm not sure what other direction I can give. Having said that, I've tested this several hundred times and this successfully retrieves the users' location in a WebApp (navigator.standalone) on iOS 6.
