Drupal -如何在JavaScript之前加载google api

我建立了一个自定义的谷歌地图实现到我的drupal网站的首页，使用javascript和php，我有一个问题，谷歌地图api不被调用，直到依赖它的php文件被调用。它在我的控制台中以以下顺序记录:

ReferenceError: google is not defined map.php:6
GET http://maps.googleapis.com/maps/api/js/AuthenticationService.Authenticate [HTTP/1.1 200 OK 74ms]

我一直在网上研究我的问题，并从不同的资源中进行了试验，但还没有任何运气。我已经提供了我试图在我的文件中调用谷歌地图api的方式。我把它放在我的页面中——front.tpl.php:

<script type="application/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>

这是我的整个map. PHP，这是PHP文件，其中包含谷歌地图与javascript和PHP，并被调用通过drupal_add_js在模板。PHP文件:

var script = document.createElement('script');
script.src = 'http://maps.googleapis.com/maps/api/js?sensor=false';
script.type = 'application/javascript';
var map = null;
var infowindow = new google.maps.InfoWindow();
var markers = [

  <?php
  $server = 'db.*****';$user = '*****';$database = '*****';$password = '*****';
  $db = mysqli_connect($server, $user, $password, $database);
  if (isset($_GET['routeselected'])) 
  {
  $result = mysqli_query($db, "SELECT * FROM STOP INNER JOIN RouteStop ON Stop.Stop_ID = RouteStop.Stop_ID WHERE RouteStop.Route_ID = " . (int)$_GET['routeselected'] . " AND RouteStop.Company_ID = " . (int)$_GET['companyselected']);
  while ($row = mysqli_fetch_array($result))
      echo "{'"title'": '".$row['Stop_ID']."', '"lat'": '".$row['Latitude']."', '"lng'": '".$row['Longitude']."', '"description'": '".$row['StopName']."'},";
  }
  ?>
];
window.onload = function () {
var mapOptions = {
    center: new google.maps.LatLng(
        parseFloat(markers[0].lat),
        parseFloat(markers[0].lng)),
    zoom: 13,
    mapTypeId: google.maps.MapTypeId.ROADMAP
};
var path = new google.maps.MVCArray();
var service = new google.maps.DirectionsService();
var infoWindow = new google.maps.InfoWindow();
var map = new google.maps.Map(document.getElementById("map"), mapOptions);
var poly = new google.maps.Polyline({map: map, strokeColor: '#F3443C'});
var lat_lng = new Array();
           for (i = 0; i < markers.length; i++) {
           var data = markers[i]
           var myLatlng = new google.maps.LatLng(data.lat, data.lng);
           lat_lng.push(myLatlng);
           var marker = new google.maps.Marker({
               position: myLatlng,
               map: map,
               title: data.title
           });
           (function (marker, data) {
               google.maps.event.addListener(marker, "click", function (e) {
                   infoWindow.setContent(data.description);
                   infoWindow.open(map, marker);
               });
           })(marker, data);
       }
for (var i = 0; i < markers.length; i++) {
    if ((i + 1) < markers.length) {
        var src = new google.maps.LatLng(parseFloat(markers[i].lat), 
                                         parseFloat(markers[i].lng));
        var des = new google.maps.LatLng(parseFloat(markers[i+1].lat), 
                                         parseFloat(markers[i+1].lng));
        service.route({
            origin: src,
            destination: des,
            travelMode: google.maps.DirectionsTravelMode.DRIVING
        }, function (result, status) {
            if (status == google.maps.DirectionsStatus.OK) {
                for (var i = 0, len = result.routes[0].overview_path.length; i < len; i++) {
                    path.push(result.routes[0].overview_path[i]);
                }
                poly.setPath(path);
            }
        });
    }
}
} 

有没有人可能知道我的问题的解决方案?谢谢你的所有帮助!