Untitled

<html>
<body>
    <form action="addchar.php" method="post">
        <select name="bookIntroduced">
            <option value="1">A Game of Thrones</option>
            <option value="2">A Clash of Kings</option>
            <option value="3">A Storm of Swords</option>
            <option value="4">A Feast for Crows</option>
            <option value="5">A Dance with Dragons</option>
        </select>
        <p>
            Page introduced:<br>
            <input type="text" name="pageIntroduced" tabindex=1 autofocus>
            <br>Title:<br>
            <input type="text" name="title" tabindex=2>
            <br>First name<br>
            <input type="text" name="forename" tabindex=3>
            <br>Surname<br>
            <input type="text" name="surname" tabindex=4>
            <br>Old surname<br>
            <input type="text" name="oldSurname" tabindex=5>
            <br>Alias or nickname<br>
            <input type="text" name="alias" tabindex=6>
            <br>Regnal number<br>
            <input type="text" name="regnalNumber" tabindex=7>
            <br>
            <input type="submit" value="Add character" tabindex=8>
        </p>
    </form>
    <?php
        // Displays the message returned from the PHP script.
        if ($_GET['msg']) {
            echo "<br>".$_GET['msg'];
        }

    ?>
</body>

<?php

if ($_POST) {
    // Configuration.
    $username = "root";
    $password = "root";
    $hostname = "localhost";
    $dbname = "asoiaf";
    $tablename = "charlist";

    // Opens a connection to the database.
    try {
        $conn = new PDO("mysql:host=$hostname;dbname=$dbname", $username, $password);
        // I don't know what this does; a
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch(PDOException $e) {
        echo $e->getmessage();
    }

    // Gets the next available primary key from the table.
    $qry = $conn->query("SELECT Auto_Increment FROM information_schema.tables WHERE table_name='$tablename'");
    // Fetches the result of the query, stores it in $result.
    $result = $qry->fetch();
    // Puts the resulting primary key into $id.
    $id = $result['Auto_Increment'];
    // Fetches all the other information from the form.
    $bookIntroduced = $_POST['bookIntroduced'];
    $pageIntroduced = $_POST['pageIntroduced'];
    $forename = $_POST['forename'];
    $surname = $_POST['surname'];
    $oldSurname = $_POST['oldSurname'];
    $alias = $_POST['alias'];
    $title = $_POST['title'];
    $regnalNumber = $_POST['regnalNumber'];

    // Queries the table to see if a record exists with the same forename and surname values.
    $qry = $conn->query("SELECT forename, surname FROM charlist WHERE forename='$forename' AND surname='$surname'");
    $result = $qry->fetch();
    // If a record with the same forename/surname exists, the entry is a duplicate entry and should be disallowed.
    if ($result[0]==$forename && $result[1]=$surname) {
        // Return to the original page reporting a duplicate error.
        header('Location: asoiaf.php?msg=duplicate error');
    } else {
        // Prepare the SQL statement.
        $sql = "INSERT INTO $tablename (id, bookIntroduced, pageIntroduced, forename, surname, oldSurname, alias, title, regnalNumber)
                VALUES (:id, :bookIntroduced, :pageIntroduced, :forename, :surname, :oldSurname, :alias, :title, :regnalNumber)";
        $q = $conn -> prepare($sql);
        // Executes the SQL.
        $q -> execute(array(':id' => $id, ':bookIntroduced' => $bookIntroduced, ':pageIntroduced' => $pageIntroduced, ':forename' => $forename, ':surname' => $surname, ':oldSurname' => $oldSurname, ':alias' => $alias, ':title' => $title, ':regnalNumber' => $regnalNumber));

        // Closes the PDO connection.
        $conn = null;

        // Returns to the original HTML page.
        header('Location: asoiaf.php?msg=success');
    }
}
?>

http://localhost/asoiaf.php?msg=%3Cscript%3Ealert(%22bad%22)%3C/script%3E

<script>alert("bad");</script>

echo $e->getmessage();

// I don't know what this does; a
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);