게시판 글 수정 시, 비밀번호 체크

<?php

$bno = $_GET['idx'];
$username = $_POST['name'];
$userpw = password_hash($_POST['pw'], PASSWORD_DEFAULT);
$title = $_POST['title'];
$content = $_POST['content'];
$sql = mq("update board set name='".$username."',pw='".$userpw."',title='".$title."',content='".$content."' where idx='".$bno."'"); ?>

<script type="text/javascript">
    alert("수정되었습니다.");

</script>
<meta http-equiv="refresh" content="0 url=../read_board.php?idx=<?php echo $bno; ?>">

<?php

$bno = $_GET['idx']; 
$sql = mq("select * from board where idx='".$bno."'"); 
$board = $sql->fetch_array();

?>
<div id='writepass'>
    <form action="" method="post">
        <p>비밀번호<input type="password" name="pw_chk" /> <input type="submit" value="확인" /></p>
    </form>
</div>
<?php
         $bpw = $board['pw'];

         if(isset($_POST['pw_chk']))
         {
             $pwk = $_POST['pw_chk']; 
            if(password_verify($pwk,$bpw)) 
            {
                $pwk == $bpw;
            ?>
<script type="text/javascript">
    location.replace("write_reset__ok.php");

</script>
<?php 
            }else{ ?>
<script type="text/javascript">
    alert('비밀번호가 틀립니다');

</script>
<?php } } ?>