Global Javascript variables defined in the function

Question

I am trying to make variables lat and loc global, but they are always zero.

var lat=0;
var loc=0;

navigator.geolocation.getCurrentPosition(function(position) {
     lat = position.coords.latitude;
     loc = position.coords.longitude;
});

alert(lat); // this eqals zero

possible duplicate of [how to change value of global variable inside of function](http://stackoverflow.com/questions/10872006/how-to-change-value-of-global-variable-inside-of-function) — David Robinson, Jul 03 '15 at 14:31
Nice, that's what I explained in my answer! @DavidRobinson! Still not a duplicate of **that** answer. — Praveen Kumar Purushothaman, Jul 03 '15 at 14:32
@PraveenKumar it seems that the function does not even start. When I put alert inside function the alert window didn't display. — Matus Mucka, Jul 03 '15 at 14:54
Great... So you need to put it to work on a device where it has an access to the location. If you are trying it on chrome on a laptop, it is tricky to get it started. The allow permissions thing doesn't come so easily for location! — Praveen Kumar Purushothaman, Jul 03 '15 at 14:55

score 2 · Answer 1 · answered Jul 03 '15 at 14:30

That's an asynchronous call! Use this way:

navigator.geolocation.getCurrentPosition(function(position) {
    lat = position.coords.latitude;
    loc = position.coords.longitude;
    alert (lat);
});

Background

When you are firing alert(lat), the getCurrentPosition() wouldn't have fired and your value might have not set. If you wanna do something, put it or call it inside that function.

navigator.geolocation.getCurrentPosition(function(position) {
    lat = position.coords.latitude;
    loc = position.coords.longitude;
    // Something like this.
    calculate (lat, loc);
});

Global Javascript variables defined in the function

1 Answers1