php - datas aren't showing after clicking event view

one text

Hello There im using a github project for a learning purpose and in that i have a option called events. in events we can add or view events and (add event working) once i click event to view this error occurs and i dont know how to fix it.so please help me with this if possible,

error name

Fatal error: Uncaught Error: Undefined constant "absolute" in C:\xampp\htdocs\Ip project\event-page.php:69 Stack trace: #0 {main} thrown in C:\xampp\htdocs\Ip project\event-page.php on line 69

in line 69 code

$diff=date_diff($date1,$date2, absolute); (this is the line 69)

datas aren't showing after clicking event view

full code if needed

    <link href="css/flipclock.css" rel="stylesheet">
</head>

<body>
    
    <?php include 'includes/navbar.php'; ?>    

    <div class="container">
        <div class="row">
            <div class="col-sm-3">

                <?php include 'includes/profile-card.php'; ?>

            </div>

            <div class="col-sm-9" id="user-section">

                <?php

                    $sql = "select e.event_date, e.event_id, e.event_by, e.title, e.event_image, i.description,
                                u.uidUsers, u.userImg, i.headline as e_headline
                            from events e, event_info i, users u
                            where e.event_id = ? 
                            and e.event_by = u.idUsers
                            and e.event_id = i.event";

                    $stmt = mysqli_stmt_init($conn);    

                    if (!mysqli_stmt_prepare($stmt, $sql))
                    {
                        die('SQL error');
                    }
                    else
                    {
                        mysqli_stmt_bind_param($stmt, "s", $eventId);
                        mysqli_stmt_execute($stmt);
                        $result = mysqli_stmt_get_result($stmt);

                        $row = mysqli_fetch_assoc($result);

                        $date1 = date_create(date("Y-m-d"));
                        $date2 = date_create($row['event_date']);

                        $diff=date_diff($date1,$date2, absolute);

                        $diff_sec = $diff->format('%r').( 
                                        ($diff->s)+ 
                                        (60*($diff->i))+ 
                                        (60*60*($diff->h))+ 
                                        (24*60*60*($diff->d))+ 
                                        (30*24*60*60*($diff->m))+ 
                                        (365*24*60*60*($diff->y)) 
                                        );      
                    }
                ?>

                <img class="blog-cover" src="uploads/<?php echo $row['event_image']; ?>">

                <img class="blog-author" src="uploads/<?php echo $row['userImg']; ?>">

                <div class="px-5">
                    <div class="text-center px-5">

                        <br><br><br>
                        <h1><?php echo ucwords($row['title']) ?></h1>
                        <br>
                        <h6 class="text-muted"><?php echo ucwords($row['e_headline']) ?></h6>
                        <br><br><br>

                        <h3>Event Countdown</h3>
                        <br>

                        <div class="clock" style="margin-left:5%;"></div>
                        <div class="message"></div>
                        <br><br><br>

                        <p class="text-justify"><?php echo $row['description'] ?></p>

                        <br><br>
                        <p class="text-muted text-left">Organized By: <?php echo ucwords($row['uidUsers']); ?></p>

                    </div>
                </div>
            </div>
        </div>
    </div>

    <script src="js/jquery.min.js"></script>
<script src="js/bootstrap.min.js"></script>
    <script src="js/flipclock.js"></script> 
    
    <script type="text/javascript">
    var clock;
    
    $(document).ready(function() {
        var clock;

        clock = $('.clock').FlipClock({
            clockFace: 'DailyCounter',
            autoStart: false,
            callbacks: {
                stop: function() {
                    $('.message').html('<br><h1 class="text-success">The Event is Happening!</h1>')
                }
            }
        });
                
        clock.setTime(<?php echo $diff_sec ?>);
        clock.setCountdown(true);
        clock.start();

    });
</script>
    
</body>

Source