问Dependent dropdown获取ids而不是名称

EN

   <form action="../form/form1.php" method="post" enctype="multipart/form-data">

<div class="frmDronpDown">
<div class="row">
<label>Training:</label><br/>
<select name="training" id="training-list" class="demoInputBox" onChange="getCourse(this.value);">
<option value="">Select Training</option>
<?php
foreach($results as $training) {
?>
<option value="<?php echo $training["id"]; ?>"><?php echo $training["training"]; ?></option>
<?php
}
?>
</select>
</div>
<div class="row">
<label>Course:</label><br/>
<select name="course" id="course-list" class="demoInputBox" onChange="getCountry(this.value);">
<option value="">Select Course</option>
</select>
</div>


<div class="row">
<label>Country:</label><br/>
<select name="country" id="country-list" class="demoInputBox" onChange="getCity(this.value);">
<option value="">Select Country</option>
</select>
</div>


<div class="row">
<label>City:</label><br/>
<select name="city" id="city-list" class="demoInputBox" onChange="getDates(this.value);">
<option value="">Select City</option>
</select>
</div>

<div class="row">
<label>Dates:</label><br/>
<select name="dates" id="dates-list" class="demoInputBox" onChange="getPrice(this.value);">
<option value="">Select Dates</option>
</select>
</div>

<div class="row">
<label>Online Onsite Price:</label><br/>
<select name="price" id="price-list" class="demoInputBox">
<option value="">Select Online or Onsite</option>
</select>
</div>
            <input id="submit" name="submit" type="submit" value="Submit">

        </form>

    <?php
require_once("dbcontroller.php");
$db_handle = new DBController();
if(!empty($_POST["training_id"])) {
    $query ="SELECT * FROM course WHERE training_id = '" . $_POST["training_id"] . "'";
    $results = $db_handle->runQuery($query);
?>
    <option value="">Select Course</option>
<?php
    foreach($results as $course) {
?>
    <option value="<?php echo $course["id"]; ?>"><?php echo $course["course"]; ?></option>
<?php
    }
}
?>