Why do I can't get the title by using POST method? - php

Question

So I am trying to get the title from the URL by using $_GET['title'] in the first PHP file, but I can't get the file on the 2nd file.
URL:
https://easy2book.000webhostapp.com/neworder.php?bookid=101&title=SENIOR%20secondary%20geography%20fieldwork%20and%20assessment%20practice%202021.%20For%20HKDSE%202021%20/%20Ip%20Kim%20Wai%20...%20[et%20al.].
1st File:
<?php
include_once 'header.php';
$id2 = mysqli_real_escape_string($conn, $_GET['bookid']);
$title2 = mysqli_real_escape_string($conn, $_GET['title']);
?>
<section class="neworder-form">
<h2>Order</h2>
<div class="neworder-form-form">
<form action="neworder.inc.php" method="post">
<table>
<tr>
<td>Book ID:</td>
<td>
<input type="text" disabled="disabled" name="bookid2" value="<?= $id2 ?>">
</td>
</tr>
<tr>
<td>Book Title: </td>
<td>
<input type="text" disabled="disabled" name="title2" value="<?= $title2 ?>">
</td>
</tr>
<tr>
<td>Username: </td>
<td>
<input type="text" name="uid2" placeholder="Username...">
</td>
</tr>
<tr>
<td>Comfirmed Book ID: </td>
<td>
<input type="text" name="id2" placeholder="Please enter the Book ID....">
</td>
</tr>
</table>
<button type="submit" name="submit2">Order</button>
</form>
</div>
<?php
// Error messages
if (isset($_GET["error"])) {
if ($_GET["error"] == "emptyinput2") {
echo "<p>Fill in all fields!</p>";
}
else if ($_GET["error"] == "usernametaken2") {
echo "<p>Username already taken!</p>";
}
}
?>
</section>
2nd File:
<?php
if (isset($_POST["submit2"])) {
// First we get the form data from the URL
$uid2 = $_POST["uid2"];
$id2 = $_POST["id2"];
$title2 = $_POST["title2"];
// Then we run a bunch of error handlers to catch any user mistakes we can (you can add more than I did)
// These functions can be found in functions.inc.php
require_once "dbh.inc.php";
require_once 'functions2.inc.php';
// Left inputs empty
// We set the functions "!== false" since "=== true" has a risk of giving us the wrong outcome
if (emptyInputOrder2($uid2,$id2) !== false) {
header("location: ../neworder.php?error=emptyinput&bookid=$id2&title=$title2");
exit();
}
// Is the username exists
if (uidExists2($conn, $uid2) !== true) {
header("location: ../neworder.php?error=undefineuser");
exit();
}
// If we get to here, it means there are no user errors
// Now we insert the user into the database
createUser($conn, $uid2, $id2);
} else {
header("location: ../neworder.php");
exit();
}

Answer 1

The input fields are disbled, disabled inputs are not posted.
Replace $title2 = $_POST[""]; with $title2 = $_POST["title2"];