"Is point in polygon" function for leaflet

isInPolygon

var isInPolygon = function (pointLanLng, polygon) {
    var n, i, j, xi, xj, yi, yj, intersect,
            inside = false,
            x = pointLanLng.lat, y = pointLanLng.lng,
            polygonLatLngs = polygon.getLatLngs();

    for (n = 0; n < polygonLatLngs.length; n = n+1) {

        for (i = 0, j = polygonLatLngs[n].length - 1; i < polygonLatLngs[n].length; j = i++) {
            xi = polygonLatLngs[n][i]['lat'];
            yi = polygonLatLngs[n][i]['lng'];
            xj = polygonLatLngs[n][j]['lat'];
            yj = polygonLatLngs[n][j]['lng'];

            intersect = ((yi > y) != (yj > y))
            && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
            if (intersect) inside = !inside;
        }
    }

    return inside;
};