function counter(debut, fin)	{

	now = new Date(debut);
	jourj = new Date(fin);

	new_debut = new Date(now.getTime() + 1000);
	new_fin = fin;

	var mois = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec");

	days = (jourj - now) / 1000 / 60 / 60 / 24;
	daysRound = Math.floor(days);

	hours = (jourj - now) / 1000 / 60 / 60 - (24 * daysRound);
	hoursRound = Math.floor(hours);

	minutes = (jourj - now) / 1000 /60 - (24 * 60 * daysRound) - (60 * hoursRound);
	minutesRound = Math.floor(minutes);

	seconds = (jourj - now) / 1000 - (24 * 60 * 60 * daysRound) - (60 * 60 * hoursRound) - (60 * minutesRound);
	secondsRound = Math.round(seconds);

	hoursRound = (hoursRound < 10) ? "0" + hoursRound : hoursRound;
	minutesRound = (minutesRound < 10) ? "0" + minutesRound : minutesRound;
	secondsRound = (secondsRound < 10) ? "0" + secondsRound : secondsRound;
	
	temps_ecoule = Math.floor(((now.getTime()-jourj.getTime())/1000)/60);

	if ( (now.getTime() >= (jourj.getTime()-20000)) && (now.getTime() < (jourj.getTime()+900000)) )	{		
		if (now.getTime() >= jourj.getTime())
			$('index_message').innerHTML = "<big>Le quiz est commenc&eacute; depuis <span style=\"color:black;\">" + temps_ecoule + "</span> minutes</big>";

		$('compteur').innerHTML = "<br /><br /><center><a href=\"javascript:;\" onClick=\"window.open(\'/questionnaire/\', \'qcm\', \'width=810,height=750,top=50,left=50,status=0,toolbar=0,scrollbars=yes,resizable=no\');\"><img src=\"/img/logo_questionnaire.gif\" border=\"0\"></a></center>";

		return;
	}
	else if (now.getTime() >= (jourj.getTime()+900000))	{
		$('compteur').innerHTML = "";
		$('index_message').innerHTML = "<big>Le quiz est termin&eacute; !!</big>";
		return;
	}
	else	{
		$('compteur_jrs').innerHTML = daysRound;
		$('compteur_hrs').innerHTML = hoursRound;
		$('compteur_mns').innerHTML = minutesRound;
		$('compteur_scs').innerHTML = secondsRound;
		if ($('compte_a_rebours'))
			$('compte_a_rebours').innerHTML = (daysRound*24 + hoursRound*1) + " heures " + minutesRound + " minutes " + secondsRound + " secondes ";
	}

	newtime = window.setTimeout("counter(new_debut, new_fin);", 1000);

}