function switchCkAlAUne(idCk)
{
	var nbCk = 4;
	for(i = 1; i <= nbCk; i++)
		{
			document.getElementById("ckALaUne"+i).style.display='none';
			document.getElementById("fleche"+i).style.visibility='hidden';
		}
	document.getElementById("ckALaUne"+idCk).style.display='block';
	document.getElementById("fleche"+idCk).style.visibility='visible';
}