ถามเรื่อง ajax กับ php หน่อยครับ - พอดีในหน้า add_hotel.php มันไม่แสดงข้อมมูลให้เลือกอ่ะครับ ไม่รู้ว่าผิดตรงไหน

<?php


include_once("../include/connectdb.inc.php");

        
     header("content-type: application/x-javascript; charset=tis-620");
     
     $data=$_GET['data'];
     $val=$_GET['val'];
     
     
         
     if ($data=='hotel') {
          $sql="select * from hotel_mst order by hotel_id";
          $result = mysql_query($sql);
          echo "<select name='hotel' style='width: 120px; border: 1px solid #336699;' onChange=\"dochange('room', this.value)\">\n";
          echo "<option value='0'>- Select -</option>\n";
         
          while($fetcharr = mysql_fetch_array($result)) { 
               $val = $fetcharr['hotel_id'];
               $label = $fetcharr['hotel_name'];
               echo "<option value=\"$val\">$label</option> \n" ;
          }
     } else if ($data=='room') {
          echo "<select name='room' style='width: 120px; border: 1px solid #336699;' onChange=\"dochange('ban', this.value)\">\n";
          $sql="select * from hotel_rmtype_mst where hotel_id = '$val'";
          $result = mysql_query($sql);
          echo "<option value='0'>- Select -</option>\n";
          
          while($fetcharr = mysql_fetch_array($result)) { 
               $val = $fetcharr['rmtype_id'];
               $label = $fetcharr['rmtype_name'];
               echo "<option value=\"$val\">$label</option> \n" ;
          }
     } 
     echo "</select>\n";  



?>