Google Maps JS API v3 - Simple multiple marker + polyline

var arr = [];
for (var i = 0; i < locations.length; i++) {
var marker = new google.maps.Marker({
position: new google.maps.LatLng(locations[i][0], locations[i][1]),
map: map
});
arr.push(marker.getPosition());
// <-- snipped -->
}
Edit:
var poly = new google.maps.Polyline({
path: arr,
strokeColor: '#000000',
strokeOpacity: 1.0,
strokeWeight: 3,
map: map
});
ref -
http://stackoverflow.com/questions/16169775/google-maps-js-api-v3-simple-multiple-marker-polyline