How navigator.geolocation.getCurrentPosition gets location coordinates of a client browser

I am using browser API for geolocation like below (codes written below are just for demo)

Clie开发者_运维问答nt Script using jQuery

       $(function () {
            $('#link-getlocation').click(function () {

                navigator.geolocation.getCurrentPosition(function(loc){
                       alert(loc.coords.latitude + ', ' + loc.coords.longitude);
                });                    
            });
        });

Html

<a href="javascript:" id="link-getlocation">Get Location</a>

Demo

http://jsfiddle.net/yhHnD/1/

My question is how browser detects the location coordinates of the user

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It depends on the capabilities of the client browser.

• If the device running the browser has GPS (f.ex. a mobile phone), it generally uses GPS based locating
• If the device is on a WLAN, the browser can utilize WLAN location data (eg. via Google Location Services)
• Otherwise it most likely will use a GeoIP database

Most of these depend on OS and browser support and can vary between browsers.