What are the limitations of using PHP for controlling client-side behavior like scroll position after a page refresh?

When using PHP for controlling client-side behavior like scroll position after a page refresh, a limitation is that PHP is a server-side language and cannot directly interact with the client's browser. To solve this issue, you can use JavaScript along with PHP to store the scroll position in a session variable on the server and then retrieve it on page load to set the scroll position accordingly. 

<?php
session_start();

if(isset($_POST['scroll_position'])){
    $_SESSION['scroll_position'] = $_POST['scroll_position'];
}

$scroll_position = isset($_SESSION['scroll_position']) ? $_SESSION['scroll_position'] : 0;
?>

<!DOCTYPE html>
<html>
<head>
    <script>
        window.onload = function(){
            window.scrollTo(0, <?php echo $scroll_position; ?>);
        }
    </script>
</head>
<body>
    <!-- Your HTML content here -->
    
    <form id="scrollForm" method="post">
        <input type="hidden" name="scroll_position" id="scroll_position">
    </form>
    
    <script>
        document.getElementById('scroll_position').value = window.scrollY;
        document.getElementById('scrollForm').submit();
    </script>
</body>
</html>

Keywords

PHP client-side behavior scroll position limitations page refresh

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