var dataobj_1, dataobj_2;
var scrollspeed = 1;

function initscroll(){
	dataobj_1 	= document.getElementById("rouler");
	dataobj_2 	= document.getElementById("rouler_bis");
	dataobj_1.style.top	=	"1px";
	thelength		=	dataobj_1.offsetHeight;
	dataobj_2.style.top	=	thelength+"px";
	scrolltest();
}

function scrolltest(){
	dataobj_1.style.top	=	parseInt(dataobj_1.style.top)-scrollspeed+"px";
	dataobj_2.style.top	=	parseInt(dataobj_2.style.top)-scrollspeed+"px";
	if (parseInt(dataobj_1.style.top)<-thelength)
		dataobj_1.style.top=thelength+'px';
	if (parseInt(dataobj_2.style.top)<-thelength)
		dataobj_2.style.top=thelength+'px';
	//Regler ici le parametre pour la vitesse
	var vitesse = 50;
	setTimeout("scrolltest()",vitesse);
}

if (document.addEventListener) {document.addEventListener("DOMContentLoaded", initscroll, false);}
else window.attachEvent('onload', initscroll);