Insert Query mit jQuery Probem

<?php
        if(isset($_POST['submit'])) {
        
        $msg = '';
        $pid = $_POST["pid"]; 
        $comment = $_POST['comment']; 
        $uid = 2; 
        
        $sql = 'INSERT INTO comments (p_id, u_id, comment) VALUES (:p_id, :u_id, :comment)'; 
        $stmts = $pdo->prepare($sql); 
        if(!$stmts) { echo $stmts->errorInfo(); } 
        $stmts->BindParam(':p_id', $pid); 
        $stmts->BindParam(':u_id', $uid); 
        $stmts->BindParam(':comment', $comment); 
         
        if(!$stmts->execute()) { 
        echo $stmts->errorInfo(); 
        } else { 
        $msg = 'Eingefügt';
        }
    }
    ?>
    <?php    while($row = $stmt->fetch()) {      ?>
            <form action="world_two.php" id="form" method="POST">
        <?php echo '<img src="data:image/' . $row['im_type'] . ';base64,' . base64_encode($row['image']) . '"/>'; ?> 
        <?php echo '' . $row['username'] . ''; ?> 
        <?php echo '<p>' . $row['date'] . '</p>'; ?> 
        <?php echo '<p><input type="hidden" name="pid" value="'.$row['p_id'].'"></p>'; ?>
        <?php echo '<p><input type="text" name="comment"></p>'; ?>
        <?php echo '<p><input type="submit" name="submit" id="submit"></p>'; ?>
        </form>
        <?php } ?>

        <span id="result">
        <?php if(isset($msg)) { echo $msg; } ?>
        </span>
        
        <script src="jQuery/jquery-3.3.1.min.js" type="text/javascript"></script>
        <script src="js/global.js"></script>

<?php    while($row = $stmt->fetch()) {      ?>
            <form action="test.php" id="form" method="POST">
        <?php echo '<img src="data:image/' . $row['im_type'] . ';base64,' . base64_encode($row['image']) . '"/>'; ?> 
        <?php echo '' . $row['username'] . ''; ?> 
        <?php echo '<p>' . $row['date'] . '</p>'; ?> 
        <?php echo '<p><input type="hidden" name="pid" value="'.$row['p_id'].'"></p>'; ?>
        <?php echo '<p><input type="text" name="comment"></p>'; ?>
        <?php echo '<p><input type="submit" name="submit" id="submit"></p>'; ?>
        <script>
        $("#form").on("submit", function(event) {
            event.preventDefault();
            $.ajax({
                type: "POST",
                url: "test.php",
                data: $(this).serialize(),
                success: function(data) {
                $("#result").append(data);
                },
            });
        });
        </script>
        </form>
        <?php } ?>

        <span id="result">
        <?php if(isset($msg)) { echo $msg; } ?>
        </span>
        
        <script src="jQuery/jquery-3.3.1.min.js" type="text/javascript"></script>
        <script src="js/global.js"></script>

<?php
        include 'config/connect.php';
    
        if(isset($_POST['submit'])) {
        
        $msg = '';
        $pid = $_POST["pid"]; 
        $comment = $_POST['comment']; 
        $uid = 2; 
        
        $sql = 'INSERT INTO comments (p_id, u_id, comment) VALUES (:p_id, :u_id, :comment)'; 
        $stmts = $pdo->prepare($sql); 
        if(!$stmts) { echo $stmts->errorInfo(); } 
        $stmts->BindParam(':p_id', $pid); 
        $stmts->BindParam(':u_id', $uid); 
        $stmts->BindParam(':comment', $comment); 
         
        if(!$stmts->execute()) { 
        echo $stmts->errorInfo(); 
        } else { 
        $msg = 'Eingefügt';
        }
    }
    ?>