MVC4 Current Location

gistfile1.js

        $(function () {
            var watchID;
            $("#watch").click(function () {
                if (Modernizr.geolocation) {
                    var nav = window.navigator;
                    if (nav != null) {
                        var geoloc = nav.geolocation;
                        watchID = geoloc.watchPosition(showMap, handle_errors);
                    }
                }
                else { $("#message").text("You'll need to enter your address manually."); }
            });
        });
        function handle_errors(error) {
            switch (error.code) {
                case error.PERMISSION_DENIED:
                    alert("User did not share geolocation data");
                    break;
                case error.POSITION_UNAVAILABLE:
                    alert("Could not detect current position");
                    break;
                case error.TIMEOUT:
                    alert("Time out");
                    break;
                default:
                    alert("Unknown error");
                    break;
            }
        }