Javascript Google Maps Geofencing Alert when current location is inside geofence area.

What have you tried which didn't actually work?  First thing to note is that Geolocation API will only work from a HTTPS site and not from a HTTP site.

This is going to go into a phonegap/Cordova app. Do I still need https?

In that case, no.  An APP can get the current position using Geolocation API without https.
You can use something like below in your javascript:

navigator.geolocation.getCurrentPosition(function(position) {
  do_something(position.coords.latitude, position.coords.longitude);
});

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and with the coordinates you'll be able to calculate against the geofencing boundaries (e.g. check the distance between your location and the center of the geofenced area, etc.) to see if the current position lies within the GeoFence.

Geolocation API: Here

Yeah I can pull out the geolocation co-odinates but how do I add the geofence?

Well, it depends on how your system implements it.  Some approaches where (x1, y1) is your target position and (x2, y2) is your current location:

• Block: check if |x2-x1| and |y2-y1| are in the allowed range separately.
• Circle (linear distance): check if ((x2-x1)^2 * (y2-y1)^2) ^ 0.5 is in the allowed range
• Path (road distance): send (x1, y1) and (x2, y2) to a mapping API (e.g. Google Maps) to retrieve the distance, and check against the allowed range.

Check out my question here which show where I am. All is working except the geofence.

Maybe you can help fix the issue.

Thanks

Here's the link:

https://www.experts-exchange.com/questions/29141524/Cannot-get-Geofence-to-appear-in-the-google-map.html#questionAdd

note the referenced question above has been deleted