PHP/JS : Dynamic Dropboxes and echoing SELECTED value

Question

我目前正在使用动态下拉菜单(可靠的选择框)。我直接从 MySQL DB 中提取值(如果你好奇我是如何得到 DB SETUP 的)。我能够获取每个表的值并相应地显示它们。我遇到的问题是回显每个选择框的 SELECTED 值。我创建了一个 JS 函数，它将请求 postfile.php，然后回显每个框的 SELECTED 值。我没有得到任何回应。我已经检查过 Firebug ，但没有发布任何内容。

我怎样才能使这项工作？还是我接近这个错误？或者，还有更好的方法？ 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-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;
    } 

Answer 1

也许您想使用 jQuery UI 自动完成功能。它更易于使用且代码更少。它也有一个远程数据源。试试这个，也许这可以解决您的问题。 http://jqueryui.com/demos/autocomplete/