问使用Google Maps API 3.34地图缩放不起作用

EN

///summary
///sets up the map
///Parameters
///-mapDivID string id for the div to place the map
///-coords object with lat and lng properties
///-zoom default zoom of map (I use 13)
///-directions optional object to display directions
function startmap(mapDivID, coords, zoom, directions) {
    var maps = new Array();
    var bounds = new Array();
    var directionsDisplay;
    var directionsService;
    // Get the div to put the map in and check to make sure it's there.
    var mapDiv = document.getElementById(mapDivID);
    if (mapDiv) {
        var options = {
            zoom: zoom,
            center: coords,
            zoomControl: true,
            zoomControlOptions: {
                postion: google.maps.ControlPosition.BOTTOM_RIGHT
            }
        };
        // we have multiple maps so we need to store them in an array by the divID so we don't overlap one or the other.
        var map = {};
        if (maps.indexOf(mapDivID) < 0) {
            maps[mapDivID] = new google.maps.Map(mapDiv, options);
            if (directions) {
                directionsDisplay = new google.maps.DirectionsRenderer;
                directionsService = new google.maps.DirectionsService;

                directionsDisplay.setMap(maps[mapDivID]);
                directionsDisplay.setPanel(document.getElementById('directions-panel'));
                var onChangeHandler = function (e) {
                    if (e.which && e.which == 13) {
                        calculateAndDisplayRoute();
                    }
                };
                document.getElementById('txtOrigin').addEventListener('keypress', onChangeHandler);
            }
        } 
        map = maps[mapDivID];

        if (bounds.indexOf(mapDivID) < 0) {
            bounds[mapDivID] = new google.maps.LatLngBounds();
        }

        return map;
    } else {
        // No map div
        console.error(mapDivID + ' not found');
    }
    return map;
}

startmap('map', {lat: -34.397, lng: 150.644}, 13, null);

#map { width: 100%; height: 100% }

<script src="http://maps.google.com/maps/api/js?libraries=drawing"></script>
<div id="map">map goes here</div>