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 

Answer 1

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);
});