var time_server = 1000 * <?php echo microtime(true); ?>;
var time_offset = time_server - (new Date()).getTime();
function time_set() {
    var local_time = new Date();
    local_time.setTime(local_time.getTime() + time_offset);
    var min = local_time.getMinutes();
    var sec = local_time.getSeconds();
    document.getElementById('local-time').innerHTML = local_time.getHours() + ':' + (min < 10 ? '0' : '') + min + ':' + (sec < 10 ? '0' : '') + sec;
}
window.setTimeout(function () { window.setInterval(time_set, 1000); time_set(); }, 1000 - time_server % 1000);