我对web编程很陌生，在创建一个简单的客户机数据库时遇到了一些问题。 我必须找到一种使用Ajax从数据库中删除客户机的方法。 我试图在不使用jQuery的情况下找到解决方案。。。 到目前为止，我设法设置了一个脚本和php代码来删除一个数据库条目； 但是，不可能在不首先刷新页面的情况下删除另一个客户端。 有人能帮我找出解决这个问题的办法吗？

my index.php中的相关部分

<?php
    require_once "CRM_DB.php";
    $clients = CRM_DB::showAll();
?>

...

<div class="container">

    <div class="row mb-4">
    <div class="col-sm-12">
        <h2>All Entries</h2>
        <table class="table">
            <thead>
                <tr>
                    <th>ID</th>
                    <th>Name</th>
                    <th>E-Mail</th>
                    <th>Comment</th>
                    <th>Created At</th>
                    <th>Updated At</th>
                    <th>Delete</th>
                    <th>Edit</th>
                </tr>   
            </thead>
            <tbody>
                <? foreach($clients as $client): ?>
                    <tr id="table-row">
                        <td><?= $client->id ?></td>
                        <td><?= $client->name ?></td>
                        <td><?= $client->email ?></td>
                        <td><?= $client->text ?></td>
                        <td><?= $client->created_at ?></td>
                        <td><?= $client->updated_at ?></td>
                        <td>
                            <form action="" class="delete-form m-0" method="post">
                                <input type="hidden" id="del-id" name="id" value="<?= $client->id ?>">
                                <input type="hidden" name="delete" id="delete" value="1">
                                <button type="submit" class="btn btn-danger btn-sm" id="delete_btn" onclick="deleteID(); return false">Delete</button>
                            </form>
                    </tr>
                <? endforeach; ?>
            </tbody>
        </table>    

....

<script type="text/javascript">

    function deleteID() {

        var id = document.getElementById('del-id').value;
        var del = document.getElementById('delete').value;
        var params = 'delete='+encodeURIComponent(del)+'&id='+encodeURIComponent(id);
        var url = 'crm.php';

        xmlhttp = new XMLHttpRequest();

        xmlhttp.onload = function() {
            if(this.readyState == 4 && this.status == 200) {
                document.getElementById('table-row').innerHTML = this.response;
                    }
                };

        xmlhttp.open("POST", url, true);
        xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        xmlhttp.send(params);
    }
</script>

crm.php

if(isset($_POST["delete"]) && isset($_POST["id"])) {
    $id = $_POST["id"];
    CRM_DB::deleteClient($id);
}

crm_db.php

    public static function deleteClient($id) {
        $db = self::db();

        $query = "DELETE FROM clients WHERE id = ?";
        $result = $db->query($query, [$id]);
        return $result;
    }

    public static function showAll() {
        $db = self::db();

        $query = "SELECT * FROM clients";
        $result = $db->query($query);

        $clientArray = [];

        for($i = 0; $i < $result->num_rows; $i++) {
            $row = $result->fetch_array();

            $client = self::convertToObject($row);
            $clientArray[] = $client;
        }
        return $clientArray;
    }

    public static function convertToObject($row) {
        return new Client($row["id"], $row["name"], $row["email"], $row["text"], $row["created_at"], $row["updated_at"]);
    }

}