单击表格行时打开信息窗口

我正在尝试从MySQL表中加载多个城市的ID，名称和位置，然后将其填充到HTML表中。还有一个谷歌地图，上面有指向这些城市的标记。

我希望当用户单击 HTML 行之一（tr 标记）时，在城市标记上弹出一个信息窗口。我正在使用PHP，Javascript和XML，没有任何jQuery。

我的网页：

<?php
   $query = "SELECT id, name, lat, lng FROM city ORDER BY id";
   $arrCities = mysql_query ($query);
?>
<div id="gmap" style="width: 550px; height: 450px"></div>
<table id="tblData">
   <tr>
       <th>ID</th>
       <th>City</th>
   </tr>
   <?php while ($row = mysql_fetch_assoc($arrCities)) { ?>
       <tr id="<?php echo $row['id']; ?>">
           <td><?php echo $row['id']; ?></td>
           <td><?php echo $row['name']; ?></td>
       </tr>
   <?php } ?>
</table>

我的PHP用于创建一个XML来填充标记（my-xml-generator.php）：

<?php
    $query = "SELECT id, name, lat, lng FROM city ORDER BY id";
    $arrCities = mysql_query ($query);
    $dom = new DOMDocument('1.0', 'utf-8');
    $node = $dom->createElement ('markers');
    $parNode = $dom->appendChild ($node);
    header('Content-type: text/xml');
    while ($row = mysql_fetch_assoc($arrCities))
    {
            $node = $dom->createElement ('marker');
            $newNode = $parNode->appendChild ($node);
            $newNode->setAttribute ('id', $row['id']);
            $newNode->setAttribute ('name', $row['name']);
            $newNode->setAttribute ('lat', $row['lat']);
            $newNode->setAttribute ('lng', $row['lng']);
    }
    echo $dom->saveXML();
?>

我的Javascript：

    var gmap = new google.maps.Map (mapDiv, options);
    var arrMarkers = []; 
    var infoWindow = new google.maps.InfoWindow;
    // add markers to the map
    DownloadUrl ("my-xml-generator.php", function(data)
    {
        var xml = data.responseXML;
        var markers = xml.documentElement.getElementsByTagName ("marker");
        for (var i = 0; i < markers.length; i++)
        {
            var id = markers[i].getAttribute("id");
            var lat = parseFloat (markers[i].getAttribute("lat"));
            var lng = parseFloat (markers[i].getAttribute("lng"));
            var pos = new google.maps.LatLng (lat, lng);

            var markerOptions =
            {
                position    : pos,
                map         : gmap,
                draggable   : false
            };
            // add the marker
            var marker = new google.maps.Marker (markerOptions);
            arrMarkers.push(marker);
            // this part of code is not working
            var tr = document.getElementById(id);
            google.maps.event.addDomListener (tr, "click",  function() { RowClick(i); });

            // add info window
            var html = '<div>' + id + '</div>';
            BindInfoWindow (marker, gmap, infoWindow, html);
        }
    });

    function BindInfoWindow (marker, map, infoWindow, html)
    {
        google.maps.event.addListener (marker, "click", function()
        {
            infoWindow.setContent (html);
            infoWindow.open (map, marker);
        });
    }

    function RowClick (i)
    {
        google.maps.event.trigger (arrMarkers[i], "click");
    }

    function DownloadUrl (url, callback)
    {
        var xhr = new XMLHttpRequest();
        xhr.onreadystatechange = function()
        {
            if (xhr.readyState == 4)
            {
                xhr.onreadystatechange = DoNothing;
                callback(xhr, xhr.status);
            }
        };
        xhr.open ('GET', url, true);
        xhr.send (null);
    }
    function DoNothing() {}

不起作用的部分是上面javascript中的这一部分：

var tr = document.getElementById(id);
google.maps.event.addDomListener (tr, "click", function() { RowClick(i); });

正确的方法是什么？

附加信息：如果我将我的 javascript 更改为这样：

var tr = document.getElementById(id);
google.maps.event.addDomListener (tr, "click", function() { alert(tr.id); });

然后，当我单击该行时会弹出警报框，但是无论我单击哪一行，显示的ID都将始终是最后一行的ID。谢谢