谷歌地图google.maps.places.PlacesService typeerror undefined

Question

几乎完全遵循以下代码：https://developers.google.com/maps/documentation/javascript/places#TextSearchRequests

当

service = new google.maps.places.PlacesService(map);

调用

，控制台给我一个未定义的类型错误：

util.js:22 Uncaught TypeError: Cannot read property 'innerHTML' of undefined

我的代码如下。有谁知道发生了什么事？

HTML

<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDo5LxyVUv5EwGQBwaveIF4d0MaIVD_Dd8&libraries=places"></script>

JS

function initMap(userLocation) {
    map = new google.maps.Map(document.getElementById('map'), {
        center: userLocation,
        zoom: radius
    });

    infowindow = new google.maps.InfoWindow();
}

function textSearch(query) {
    var service;

    var request = {
        location: userLocation,
        query: query
    };

    service = new google.maps.places.PlacesService(map);
    service.textSearch(request, cb);
}

function cb(results, status) {
    if (status == google.maps.places.PlacesServiceStatus.OK) {
        for (var i = 0; i < results.length; i++) {
            var place = results[i];
            // createMarker(results[i]);
            console.log(place);
        }
    }
}

initMap(userLocation); // userLocation is a latLong obj, set elsewhere in the code.
textSearch('movies');