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我目前正在使用動態下拉菜單（可靠的選擇框）。我直接從MySQL數據庫拉值（如果你在這裏好奇的是我如何有DB SETUP）。我能夠獲取每個表的值並相應地顯示它們。我遇到的問題是迴應每個selct框的SELECTED值。我有一個創建的JS函數，它會請求postfile.php，然後它會回顯每個框的SELECTED值。我沒有得到任何迴應。我已經檢查過螢火蟲，但沒有發佈任何內容。PHP/JS：動態Dropboxes和回顯SELECTED值
我該如何做這項工作？或者我接近這個錯誤？或者，還有更好的方法？ EXAMPLE
工作HTML/PHP
<?php
include ('includes/dbConnect.php');
try {
$pdo = get_database_connection();
$sql = "SELECT *
FROM `categories`
WHERE `master_id` = 0";
$statement = $pdo->query($sql);
$list = $statement->fetchAll(PDO::FETCH_ASSOC);
} catch(PDOException $e) {
echo 'There was a problem';
}
?>
<select name="main" id="main" size="7" class="update">
<option value="">Select one</option>
<?php if (!empty($list)) { ?>
<?php foreach($list as $row) { ?>
<option value="<?php echo $row['id']; ?>">
<?php echo $row['name']; ?>
</option>
<?php } ?>
<?php } ?>
</select>
<select name="subc1" id="subc1" size="7" class="update" disabled="disabled" hidden="hidden">
<option value="">----</option>
</select>
<select name="subc2" id="subc2" size="7" class="update" disabled="disabled" hidden="hidden">
<option value="">----</option>
</select>
<select name="subc3" id="subc3" size="7" class="update" disabled="disabled" hidden="hidden">
<option value="">----</option>
</select>
JS
<script type="text/javascript">
$(document).ready(function() {
$('#main).change(function() {
if ($(this).val()!='
') {
$("#subc1").load("postfile.php",{main_id: $(this).val()});
//$("#subc1").removeAttr('
disabled hidden ');
}
});
//code on change of sel_source
$('#subc1 ').change(function() {
if ($(this).val()!='
') {
$("#subc2").load("postfile.php",{subc1_id: $(this).val()});
//$("#colour").removeAttr('
disabled ');
}
});
$('#subc2 ').change(function() {
if ($(this).val()!='
') {
$("#subc3").load("postfile.php",{subc2_id: $(this).val()});
//$("#colour").removeAttr('
disabled ');
}
});
});
</script>
PHP的postfile.php
if(isset($_REQUEST['main_id']) && !empty($_REQUEST['main_id'])) {
try {
include ('../includes/dbConnect.php');
$pdo = get_database_connection();
$sql = ("select * from `categories` where id='".$_REQUEST['main_id']."' ");
$result = $con->prepare($sql);
$result->execute();
$number_of_rows = $result->fetchColumn();
}catch(PDOException $e) {
echo 'There was a problem';
}
if($number_of_rows > 0) {
$output = '<option value="">Select</option>';
while($row = mysql_fetch_assoc($result)) {
$output .= '<option value="'.$row['id'].'">'.$row['name'].'</option>';
}
} else {
$output = '<option value="">Select</option>';
}
echo $output;
}
if(isset($_REQUEST['subc1_id']) && !empty($_REQUEST['subc1_id'])) {
$result = mysql_query("select * from table where id='".$_REQUEST['subc1_id']."' ");
if($number_of_rows > 0) {
$output = '<option value="">Select</option>';
while($row = mysql_fetch_assoc($result)) {
$output .= '<option value="'.$row['id'].'">'.$row['name'].'</option>';
}
} else {
$output = '<option value="">Select</option>';
}
echo $output;
}
if(isset($_REQUEST['subc2_id']) && !empty($_REQUEST['subc2_id'])) {
$result = mysql_query("select * from table where id='".$_REQUEST['subc2_id']."' ");
if($number_of_rows > 0) {
$output = '<option value="">Select</option>';
while($row = mysql_fetch_assoc($result)) {
$output .= '<option value="'.$row['id'].'">'.$row['name'].'</option>';
}
} else {
$output = '<option value="">Select</option>';
}
echo $output;
}