Javascript 为什么谷歌地图中的下拉列表不可点击？

我正在使用GoogleMapsAPI，其中我正在使用ajax加载两个下拉列表。这两个下拉列表都是不可点击的，我正在使用tab按钮在下拉列表中进行更改，有人能帮我解决这个问题吗

这是html

<div id="Layer1">
    <select name="delivery_center" id="delivery_center">
        <option value="">--Please Select--</option>
        <?php foreach($DeliveryCenters as $dlvryData):?>
        <option value="<?php if($dlvryData['delivery_center_name'] == 'Chennai') echo 'Others';else echo $dlvryData['delivery_center_name'];?>" <?php if(isset($_GET['rgn']) && $dlvryData['delivery_center_name']==$_GET['rgn']) echo "selected";?>><?php echo $dlvryData['delivery_center_name'];?></option>
        <?php endforeach;?>
    </select>
</div>
<div id="Layer2">
    <select name="myList3[]" id = "myList3" onchange="loadPg(this.value)">
        <option value="">--Please Select--</option>
        <?php foreach($acName as $acData):?>
        <option value="<?php echo $acData['AccountName'];?>" <?php if(isset($_GET['acId']) && $acData['AccountName']==$_GET['acId']) echo "selected";?>><?php echo $acData['AccountName'];?></option>
        <?php endforeach;?>            
    </select>
</div>

---

请提供一个演示您的问题的示例。我们不知道数据库的内容，因此请通过browser->ViewSource发布可用的HTML。我认为，即使是屏幕截图也有助于了解当前行为和预期行为。

         var geocoder;
    var directionsService;
    var directionsDisplay;
    var markers = [];
    var map;
    //Start of code (above is framework)  
    function initialize() {
        var myLatLng = new google.maps.LatLng(16.341130, -5.390013);
        var mapOptions = {
            zoom: 2,
            center: myLatLng,
            mapTypeId: google.maps.MapTypeId.ROADMAP,
            disableDefaultUI: true,

        };
        //Map Framework above
        var map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions); //Map Options

        //google.maps.event.addDomListener(document.getElementById('SelectList'),
        //  'change', function() {}
        //var mypos = document.getElementById('SelectList').value;

        <?php
        if(isset($_GET['acId']))
        {
  $incVal = 1;
  if($_GET['rgn'] == 'India'){
  $info = $func->getIndiaAccountsData($con, $_GET['acId']);}
  else
  $info = $func->getRegionwiseAccountsData($con, $_GET['rgn'], $_GET['acId']);

  $cityArr = $info[0];
$ledArr = array("Breached", "InOrder", "CheckPointed");
$fnArr = $info[1];
$dupArr = array_count_values($info[2]);

$olaHydFinal = "";$olaNoiFinal = "";$olaOthFinal = "";

$unqcityArr = array_values(array_unique($cityArr));
print_r($unqcityArr);echo '<br>';print_r($fnArr);echo '<br>';print_r($dupArr);echo '<br>';

for ($inc1=0;$inc1<count($unqcityArr);$inc1++){
    $coOrd = $coRes['Impacted_Locations'].",";
    //$coOrd = substr($coOrd,0,-1); 
    $spt0 = explode(",", $coOrd);//print_r($spt0);echo count($spt0);
    for($inc=0;$inc<count($spt0);$inc++){
      if($spt0[$inc]!=""){
        $coQry1Cnt = mysqli_num_rows(mysqli_query($con, "select * from coordinates_mst where Coordinate_Name='".$spt0[$inc]."'"));
                    if($coQry1Cnt>0){
                    $coQry1 = mysqli_fetch_assoc(mysqli_query($con, "select * from coordinates_mst where Coordinate_Name='".$spt0[$inc]."'"));
        ?>
        // Marker<?php echo $incVal;?> (Red - default marker color)
        var latLng<?php echo $incVal;?> = new google.maps.LatLng(<?php echo $coQry1['latitude'];?>, <?php echo $coQry1['longitude'];?>);
        var contentString<?php echo $incVal;?> = "<div id='content'><a onclick=\"window.open(\'incident-details.php?id=<?php echo $coRes['Incident_Number'];?>\',\'Incident Summary\',\'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=no, width = 950, top=150, left=200\');\"><?php echo $coRes['Incident_Number'];?></a></div>";
        var infowindow<?php echo $incVal;?> = new google.maps.InfoWindow({
            content: contentString<?php echo $incVal;?>
        });

        var marker<?php echo $incVal;?> = new google.maps.Marker({
            position: latLng<?php echo $incVal;?>,
            icon: src = 'Images/rednew1.gif',
            optimized: false,
            //new google.maps.Size(42,68)
            //size: (12, 10),
            //position: mypos,
            map: map,
            title: "<?php echo $coQry1['Coordinate_Name'];?>" //hover 
        });

        markers[<?php echo $incVal;?>] = marker<?php echo $incVal;?>;

        google.maps.event.addListener(marker<?php echo $incVal;?>, 'click', function () {
            infowindow<?php echo $incVal;?>.open(map, marker<?php echo $incVal;?>);

        });

        //moved 'SelectList' up toward top!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

        // End code for Marker
    <?php $incVal++;}}}}}else{

                $incVal = 1;
        foreach($acName as $acData):
        $coQry = mysqli_query($con, "select * from map_coordinates where Account_id=".$acData['Id']);
        while($coRes = mysqli_fetch_assoc($coQry)){
            $coOrd = $coRes['Coordinate_id'].",";
            //$coOrd = substr($coOrd,0,-1);
            $spt0 = explode(",", $coOrd);//print_r($spt0);echo count($spt0);
            for($inc=0;$inc<count($spt0);$inc++){
                if($spt0[$inc]!=""){
                    $coQry1Cnt = mysqli_num_rows(mysqli_query($con, "select * from coordinates_mst where id=".$spt0[$inc]));
                    if($coQry1Cnt>0){
                    $coQry1 = mysqli_fetch_assoc(mysqli_query($con, "select * from coordinates_mst where id=".$spt0[$inc]));
        ?>
        // Marker<?php echo $incVal;?> (Red - default marker color)
        var latLng<?php echo $incVal;?> = new google.maps.LatLng(<?php echo $coQry1['latitude'];?>, <?php echo $coQry1['longitude'];?>);
        var contentString<?php echo $incVal;?> = '<div id="content"><?php echo $coQry1['Coordinate_Name'];?></div>';
        var infowindow<?php echo $incVal;?> = new google.maps.InfoWindow({
            content: contentString<?php echo $incVal;?>
        });

        var marker<?php echo $incVal;?> = new google.maps.Marker({
            position: latLng<?php echo $incVal;?>,
            icon: src = 'Images/rednew1.gif',
            optimized: false,
            //new google.maps.Size(42,68)
            //size: (12, 10),
            //position: mypos,
            map: map,
            title: "<?php echo $acData['Id'];?>" //hover 
        });

        markers[<?php echo $incVal;?>] = marker<?php echo $incVal;?>;

        google.maps.event.addListener(marker<?php echo $incVal;?>, 'click', function () {
            infowindow<?php echo $incVal;?>.open(map, marker<?php echo $incVal;?>);

        });

        //moved 'SelectList' up toward top!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

        // End code for Marker
        <?php $incVal++;}
                }
            }
        }endforeach;
    }?>

     }
  google.maps.event.addDomListener(window, 'load', initialize);

  function loadPg(str) {alert(1);
    window.location.href='loadaccounts.php?acId='+encodeURIComponent(str);
    }

    #Layer1 {

width:900px;
height:250px;
z-index:30;
left: 1%;
top: 25px;
visibility: visible;
overflow: visible;
 }
#Layer2 {
position:absolute;
width:600px;
height:250px;
z-index:30;
left: 1%;
top: 50px;
visibility: visible;
overflow: visible;
 }