问如何使用PHP更改某个元素的内容？

EN

//Code Used:

//index.php: https://pastebin.com/SqyUFFqq
//dbc.php: https://pastebin.com/rHVufmmc

//(You guys seem to have something against pastebin, sorry if i broke the shadow protocol)

<!-- alright you win, here you go -->
<!-- heres the main thing that does the sql stuff
<?php
  <!-- dbc.php is just setting vars to connect to the mysql db -->
  require_once("../../../dbc.php");
  if (isset($_POST['submit'])){
    $name = $_POST['name'];
    $feedback = $_POST['feedback'];

    $query = "INSERT INTO feedback (id, name, feedback, date) VALUES (NULL, ?, ?, NOW())";
    $stmt = mysqli_prepare($dbc, $query);

    mysqli_stmt_bind_param($stmt, "ss", $name, $feedback);
    mysqli_stmt_execute($stmt);

    $affro = mysqli_stmt_affected_rows($stmt);
    if ($affro == 1) {
      echo "<h1>Submitted!</h1>";
      mysqli_stmt_close($stmt);
      mysqli_close($dbc);
    } else {
      echo "Error! Could not submit data. <br>";
      echo mysqli_error($dbc);
      mysqli_stmt_close($stmt);
      mysqli_close($dbc);
    }
  }
 ?>