Javascript 没过多久，大问题就解决了。我有几个问题，这就是其中之一。这段代码工作得很好，对我帮助很大。非常感谢。 <?php require 'php/dbconnect.php'; $records = array(); if(!empty($_POST))

---

没过多久，大问题就解决了。我有几个问题，这就是其中之一。这段代码工作得很好，对我帮助很大。非常感谢。

<?php require 'php/dbconnect.php';
$records = array();
if(!empty($_POST)) {
    switch (true) {
        case isset($_POST['insert']):
            if(isset($_POST['name'], $_POST['designation'], $_POST['rank'], $_POST['currentScore'])) {
                // The following trim functions followed by !empty ensures that a series of spaces is not accepted from users as input.
                $name = trim($_POST['name']);
                $designation = trim($_POST['designation']);
                $rank = trim($_POST['rank']);
                $currentScore = trim($_POST['currentScore']);

                if(!empty($name) && !empty($designation) && !empty($rank) && !empty($currentScore)) {

                    $insert = $conn->prepare("INSERT INTO members (name, designation, rank, currentScore) VALUES (?,?,?,?)");
                    $insert->bind_param('ssii' , $name, $designation, $rank, $currentScore);

                    if($insert->execute()) {
                        $insert->free(); //Remove Query Data from memory since it is no longer needed.
                        header('location: index.php');
                        die();
                    }
                }
            }
        break;

        case isset($_POST['update']):
            $name = trim($_POST['name']);
            if(!empty($name)) {
            $update = $conn->prepare("UPDATE members SET name = ? WHERE '$memberID'");
            $update->bind_param('s', $name);
                if($update->execute()) {
                        header('location: index.php');
                        die();
                    }
            }
        break;

//      case isset($_POST['delete']):
//          // Delete statement goes here
//      break;
//      else 
    }
}
if($results = $conn->query("SELECT *, ((previousScore + currentScore) / 2) AS avgScore FROM members")) {
    if($results->num_rows) {
        while($row = $results->fetch_object()) {
            $records[] = $row; //Appending value to array
        }
        $results->free();
    }
}
?>

<?php include 'header.php' ?>
     <?php if(!count($records)) {
        echo 'No Records' ;
     } else {
     ?>
    <form id="memberSelect" method="post">
        <select name="memberID" id="members" onchange="change()">
            <!-- Populated with function members in footer.php -->
        </select>
    </form>
        <table>
            <thead>
                <tr>
                    <th>Name</th>
                    <th>Designation</th>
                    <th>Rank</th>
                    <th>Previous Score</th>
                    <th>Current Score</th>
                    <th>Average Score</th>
                </tr>
            </thead>
            <tbody>
                <?php
                foreach($records as $r) {
                ?>

                <tr>
                    <td><?php echo escape($r->name); ?></td>
                    <td><?php echo escape($r->designation); ?></td>
                    <td><?php echo escape($r->rank); ?></td>
                    <td><?php echo escape($r->previousScore); ?></td>
                    <td><?php echo escape($r->currentScore); ?></td>
                    <td><?php echo escape($r->avgScore); ?></td>
                    <!-- Remember when putting data in that current score needs to be moved to previous score's
                    position and the NEW score will take the place of current score(which will be the old score until updated) -->
                </tr>
                <?php 
                }
                ?>
            </tbody>
        </table>
    <?php
    }
    ?>

    <hr>

    <form action="" method="post">
        <div class="field">
            <label for="name">Member name</label>
            <input type="text" name="name" id="name" autocomplete="off">
        </div>
        <div class="field">
            <label for="designation">Designation</label>
            <input type="text" name="designation" id="designation" autocomplete="off">
        </div>
        <div class="field">
            <label for="rank">Rank</label>
            <input type="text" name="rank" id="charLevel" autocomplete="off">
        </div>
        <div class="field">
            <label for="currentScore">Current Score</label>
            <input type="text" name="currentScore" id="currentScore" autocomplete="off">
        </div>
        <div id="submit">
            <!-- Add a comment section to be input into DB -->
            <input type="submit" name="insert" value="Insert">
            <input type="submit" name="update" value="Update">
            <input type="submit" name="delete" value="Delete">
            <!-- <input type="hidden" name="id" value="<?php //echo $?>"> -->
        </div>
    </form>
<?php include 'footer.php' ?>

</div>

        <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
        <script>window.jQuery || document.write('<script src="js/vendor/jquery-1.11.3.min.js"><\/script>')</script>
        <script src="js/plugins.js"></script>
        <script src="js/main.js"></script>
        <script>
            //How do you explain something you barely understand? The following function uses JQUERY
            //json, and ajax to fill a select dropdown with items populated from a linked database.
            //See the jsonData.php for the json data being referenced here, it is imperitive to the operation of
            //this function that json data be available.
            function members(){
                $('#members').empty();//Removes all content of the associated ID 'members' to ensure a clean default value
                $('#members').append("<option>Loading</option>");//fill them with a default message
                $.ajax({
                    type:"POST",
                    url:"php/jsonData.php",//the location of the json data, for this it is required to be in its own file
                    contentType:"application/json; charset=utf-8",
                    dataType: "json",
                    success: function(records){ //only fires if the json data is found
                        $('#members').empty();//If everything is ok, removes previous default value
                        $('#members').append("<option value='0'>--Select Member--</option>");
                        $.each(records,function(i,memberID){//Uses a foreach loop to fire a function for every memberID, assigning the value to i
                            $('#members').append('<option value="'+ records[i].memberID +'">'+ records[i].name +'</option>');
                            //^ The workhorse. Grabs the select value by the ID, appends the option value by looking within the records array
                            //(which is defined and assigned values in the jsonData.php file) and assigns the member id as the value and the 'name'
                            //as the option. This populates the dropdown with the names and gives them the value 'memberID' from the database.
                        });
                    },
                    complete: function(){
                     }
                });
            }
            $(document).ready(function(){
                members();
            });
        </script>
        <script>
            function change(){
                $('#memberSelect').submit();//Submits the page to the server when called
            }
        </script>

        <!-- Google Analytics: change UA-XXXXX-X to be your site's ID. -->
        <script>
            (function(b,o,i,l,e,r){b.GoogleAnalyticsObject=l;b[l]||(b[l]=
            function(){(b[l].q=b[l].q||[]).push(arguments)});b[l].l=+new Date;
            e=o.createElement(i);r=o.getElementsByTagName(i)[0];
            e.src='https://www.google-analytics.com/analytics.js';
            r.parentNode.insertBefore(e,r)}(window,document,'script','ga'));
            ga('create','UA-XXXXX-X','auto');ga('send','pageview');
        </script>
    </body>
</html>

$update = $conn->prepare("UPDATE members SET name = ? WHERE '$memberID'");

$update = $conn->prepare("UPDATE members SET name = ? WHERE member_id = ?");
$update->bind_param('si', $name, $memberID);