create php live clock

You can use ajax.

timestamp.php

<?php
    date_default_timezone_set('YOUR TIMEZONE');
    echo $timestamp = date('H:i:s');

jQuery

$(document).ready(function() {
    setInterval(timestamp, 1000);
});

function timestamp() {
    $.ajax({
        url: 'http://localhost/timestamp.php',
        success: function(data) {
            $('#timestamp').html(data);
        },
    });
}

HTML

<div id="timestamp"></div>