var position;
var positionMax;
var positionMin;
var vitesse = 50;
var pause = false;

function cl(div)
{
	position = document.getElementById(div).style.top.replace("px","");
	if (position<positionMin)
		position=positionMax;
	
	if(!pause)
	document.getElementById(div).style.top=(position-1)+"px";
	
	setTimeout("cl('"+div+"')", vitesse);
}