L.control.locate().addTo(map);

L.control.locate({
	position: 'topleft',  // set the location of the control
    layer: undefined,  // use your own layer for the location marker, creates a new layer by default
    drawCircle: true,  // controls whether a circle is drawn that shows the uncertainty about the location
    follow: false,  // follow the user's location
    setView: true, // automatically sets the map view to the user's location, enabled if `follow` is true
    keepCurrentZoomLevel: false, // keep the current map zoom level when displaying the user's location. (if `false`, use maxZoom)
    stopFollowingOnDrag: false, // stop following when the map is dragged if `follow` is true (deprecated, see below)
    remainActive: false, // if true locate control remains active on click even if the user's location is in view.
    markerClass: L.circleMarker, // L.circleMarker or L.marker
    circleStyle: {},  // change the style of the circle around the user's location
    markerStyle: {},
    followCircleStyle: {},  // set difference for the style of the circle around the user's location while following
    followMarkerStyle: {},
    icon: 'fa fa-map-marker',  // class for icon, fa-location-arrow or fa-map-marker
    iconLoading: 'fa fa-spinner fa-spin',  // class for loading icon
    iconElementTag: 'span',  // tag for the icon element, span or i
    circlePadding: [0, 0], // padding around accuracy circle, value is passed to setBounds
    metric: true,  // use metric or imperial units
    onLocationError: function(err) {alert(err.message)},  // define an error callback function
    onLocationOutsideMapBounds:  function(context) { // called when outside map boundaries
            alert(context.options.strings.outsideMapBoundsMsg);
    },
    showPopup: true, // display a popup when the user click on the inner marker
    strings: {
        title: "Show me where I am",  // title of the locate control
        metersUnit: "meters", // string for metric units
        feetUnit: "feet", // string for imperial units
        popup: "You are within {distance} {unit} from this point",  // text to appear if user clicks on circle
        outsideMapBoundsMsg: "You seem located outside the boundaries of the map" // default message for onLocationOutsideMapBounds
    },
    locateOptions: {}  // define location options e.g enableHighAccuracy: true or maxZoom: 10
}).addTo(map);

// create control and add to map
var lc = L.control.locate().addTo(map);

// request location update and set location
lc.start();

var lc = L.control.locate().addTo(map);
map.on('dragstart', lc._stopFollowing, lc);

map.on('startfollowing', function() {
    map.on('dragstart', lc._stopFollowing, lc);
}).on('stopfollowing', function() {
    map.off('dragstart', lc._stopFollowing, lc);
});

L.Control.MyLocate = L.Control.Locate.extend({
   drawMarker: function() {
     // override to customize the marker
   }
});

var lc = new L.Control.MyLocate();

map.addControl(L.control.locate({
       locateOptions: {
               maxZoom: 10
}}));