function setMarge(){	
	
	
	var haut = (document.documentElement.clientHeight);
	var obj = document.getElementById('tout');
	
	
	//alert(haut);
	
	var h = (haut-645)/2;
	//alert(h);
	if(h<0)h=0;
	
	obj.style.marginTop=h+"px";
	//alert(haut);
}