function updateTime_callback()
{
        if (xmlTime.readyState==4 && xmlTime.status==200)
        {
                var html=xmlTime.responseText;
                if(html.length>0)
                {
			document.getElementById('heure_top').innerHTML=html;
                }
                current_time=parseInt(xmlTime.responseText);
        }
}
function updateTime()
{
        xmlTime.open( "GET", '/current_date.php?ts='+(new Date()).getTime(), true );
        xmlTime.send();
        setTimeout("updateTime()",20000);
}
var xmlTime=new XMLHttpRequest();
xmlTime.onreadystatechange=updateTime_callback;