两个下拉菜单MySQL和PHP

我正在创建一个php搜索。我从数据库中选择了 2 个菜单结果。第一个菜单工作正常，但第二个菜单没有。你能帮帮我吗？

这是我的家.php

<?php
require("ConfigPage.php");
$sql="SELECT LocationName
FROM tblplacelocation
Join tblplace ON tblplace.PlaceID=tblplacelocation.PlaceID
Join tbllocation ON tbllocation.LocationID=tblplacelocation.LocationID
where PlaceType='Hotels'" ;
$result = mysql_query($sql,$con);
echo '<form><P style="color:white;">Region</P>
<select name="PlaceID" onchange="showUser(this.value)">
<option value="">Region:</option>';
while($data = mysql_fetch_array($result))
  {
  $id= $data['PlaceID'];
  $lname = $data['LocationName'];
  echo "<option value='". $lname. "'>".$lname."</option>";
  }
echo "</select></form>";
echo "<div id='txtHint'></div>";
echo "<div id='divImage'></div>";?>

这是获取者.php

<?php
$q = intval($_GET['q']);
include("ConfigPage.php");
$sql="SELECT PlaceName
FROM tblplacelocation
Join tblplace ON tblplace.PlaceID=tblplacelocation.PlaceID
Join tbllocation ON tbllocation.LocationID=tblplacelocation.LocationID
 WHERE LocationName = '".$q."' AND PlaceType='Hotels'";
$result = mysql_query($sql,$con);
echo '<form><P style="color:white;">Place Name</P>
<select name="adminID" onchange="showImages(this.value)">
<option value="">Select a place:</option>';
while($data = mysql_fetch_array($result))
  {
  $pid= $data['LocationName'];
  $pname = $data['PlaceName'];
  echo "<option value='". $pid. "'>".$pname."</option>";
  }
echo "</select></form>";
mysql_close($con);
?>

这是 Java 脚本：

function showUser(str)
{
if (str=="")
  {
  document.getElementById("txtHint").innerHTML="";
  return;
  } 
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
    }
  }
xmlhttp.open("GET","getuser.php?q="+str,true);
xmlhttp.send();
}

我不知道怎么了。第一个菜单显示结果，但第二个菜单不包含任何内容。