What are the limitations of using PHP for real-time countdowns on a webpage?

PHP is a server-side language, which means it cannot update content on a webpage in real-time without refreshing the page. To create a real-time countdown on a webpage, you would need to use a client-side language like JavaScript that can interact with the webpage without requiring a full page reload.

<?php
// This is an example of using PHP to generate JavaScript code for a real-time countdown
// This code snippet will output JavaScript that updates the countdown every second

echo '<script>';
echo 'function updateCountdown() {';
echo '  var countdownDate = new Date("Dec 31, 2022 23:59:59").getTime();';
echo '  var now = new Date().getTime();';
echo '  var distance = countdownDate - now;';
echo '  var days = Math.floor(distance / (1000 * 60 * 60 * 24));';
echo '  var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));';
echo '  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));';
echo '  var seconds = Math.floor((distance % (1000 * 60)) / 1000);';
echo '  document.getElementById("countdown").innerHTML = days + "d " + hours + "h " + minutes + "m " + seconds + "s ";';
echo '}';
echo 'setInterval(updateCountdown, 1000);'; // Update countdown every second
echo '</script>';
?>