使用PHP/MMySQL在谷歌地图上形成标记的XML文件

我正试图通过从数据库中提取信息来在我的谷歌地图画布上放置标记，我从https://developers.google.com/maps/articles/phpsqlajax_v3尽管不知何故它不起作用（可能是因为我改变了一些事情，尽管我找不到是什么引起了问题。）

我已经通过使用phptoxml.php文件获取了数据，伪输出证明了这是正确的，我想：

<users>
<user id="1" name="John Tucker" age="19" lat="47.608940" lng="-122.340141" type="0"/>
<user id="2" name="Dean Jester" age="21" lat="51.219040" lng="4.326590" type="0"/>
<user id="3" name="Joris Nisteven" age="26" lat="51.203671" lng="4.341480" type="0"/>
<user id="4" name="Joske Vermeulen" age="20" lat="51.204155" lng="4.327018" type="0"/>
<user id="5" name="Timmy den Beir" age="21" lat="51.209263" lng="4.339720" type="0"/>
<user id="6" name="Ben von Duppen" age="23" lat="51.168308" lng="4.394287" type="0"/>
</users>

现在是我用来获取数据并将其放入变量中的代码：

downloadUrl("phptoxml.php", function(data) {
        var xml = data.responseXML;
        var users = xml.documentElement.getElementsByTagName("user");
        for (var i = 0; i < users.length; i++) {
            var id = parseInt(users[i].getAttribute("id"));
            var name = users[i].getAttribute("name");
            var age = parseInt(users[i].getAttribute("age"));
            var lat = parseFloat(users[i].getAttribute("lat"));
            var lng = parseFloat(users[i].getAttribute("lng"));
            var marker = add_marker(lat,lng,id,name,age); // pass in as Latitude, then Longitude
            fluster.addMarker(marker);
        }
    });

fluster用于集群管理，函数add_marker以前工作得很好，所以我怀疑这可能是问题所在。

函数downloadUrl定义如下（尽管这部分代码对我来说相当模糊）

function downloadUrl(url, callback) {
      var request = window.ActiveXObject ?
          new ActiveXObject('Microsoft.XMLHTTP') :
          new XMLHttpRequest;
      request.onreadystatechange = function() {
        if (request.readyState == 4) {
          request.onreadystatechange = doNothing;
          callback(request, request.status);
        }
      };
      request.open('GET', url, true);
      request.send(null);
    }

我注意到，如果我在request.send（null）后面放了一个警报；带有调试信息时，它不会弹出。对于downloadUrl调用后出现的任何警报也是如此。。

我不知道，希望有人能帮忙：）

Ty提前

有关更多信息，我包括整个代码：

 <script type="text/javascript">

var map; var fluster; var infoBubble;
  function initialize() {
    var latlng = new google.maps.LatLng(27.059125784374068,-37.6171875);
    var myOptions = {
    zoom: 3,
    center: latlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP,
    mapTypeControl: false,
    streetViewControl: false
};
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
fluster = new Fluster2(map);

// Change this depending on the name of your PHP file
downloadUrl("phptoxml.php", function(data) {
    var xml = data.responseXML;
    var users = xml.documentElement.getElementsByTagName("user");
    for (var i = 0; i < users.length; i++) {
        var id = parseInt(users[i].getAttribute("id"));
        var name = users[i].getAttribute("name");
        var age = parseInt(users[i].getAttribute("age"));
        var lat = parseFloat(users[i].getAttribute("lat"));
        var lng = parseFloat(users[i].getAttribute("lng"));
        var marker = add_marker(lat,lng,id,name,age); // pass in as Latitude, then Longitude
        fluster.addMarker(marker);
    }
});
var input = document.getElementById('searchTextField');
var autocomplete = new google.maps.places.Autocomplete(input);
autocomplete.bindTo('bounds', map);
google.maps.event.addListener(autocomplete, 'place_changed', function() {
    var place = autocomplete.getPlace();
    if (place.geometry.viewport) {
        map.fitBounds(place.geometry.viewport);
    } else {
        map.setCenter(place.geometry.location);
        map.setZoom(17);  // Why 17? Because it looks good.
    }
    var address = '';
    if (place.address_components) {
        address = [(place.address_components[0] &&
                    place.address_components[0].short_name || ''),
                   (place.address_components[1] &&
                    place.address_components[1].short_name || ''),
                   (place.address_components[2] &&
                    place.address_components[2].short_name || '')
                  ].join(' ');
    }
});
// Initialize Fluster
// This will set event handlers on the map and calculate clusters the first time.
fluster.initialize();   

 }


 function add_marker(lat,lng,id,name,age) {
var marker = new google.maps.Marker({
      position: new google.maps.LatLng(lat,lng),
      map: map,
      icon: 'suiticon.png',
      title: name
});
    var infoBubble = new InfoBubble({
      maxWidth: 300,
      backgroundColor: '#dedddd',
      borderWidth: 2,
      borderColor: 'rgb(68, 68, 68)'
    });
    var contentString = '<div id="content">'+
        /*'<h2>'+name+'</h2>'+
        '<p><span class="myLabel" style="margin-right:10px">'+age+'</span>21</p>'+
        '<p><center><img src="'+id+'.jpg" class="bro_image"></center> </p>'+
        '<p><button class="button_inverse" style="padding-left: 23px; padding-right:23px; margin-left:31px;" href="#">Rate this Bro!</button></p>'+
        */'</div>';
    var div = document.createElement('DIV');
    div.innerHTML = 'No pictures uploaded by this user.';
    infoBubble.addTab('Personal', contentString);
    infoBubble.addTab('Pictures', div);
    google.maps.event.addListener(marker, 'click', function() {
      if (!infoBubble.isOpen()) {
        infoBubble.open(map, marker);
      }
    }); 
return marker;

}

function addTab() {
    var title = document.getElementById('tab-title').value;
    var content = document.getElementById('tab-content').value;
    if (title != '' && content != '') {
      infoBubble.addTab(title, content);
    }
}
function downloadUrl(url, callback) {
  var request = window.ActiveXObject ?
      new ActiveXObject('Microsoft.XMLHTTP') :
      new XMLHttpRequest;
  request.onreadystatechange = function() {
    if (request.readyState == 4) {
      request.onreadystatechange = doNothing;
      callback(request, request.status);
    }
  };
  request.open('GET', url, true);
  request.send(null);
}
</script>