im1 = new Image();
im1.src= "img/menu1a.gif";
im2 = new Image();
im2.src= "img/menu2a.gif";
im3 = new Image();
im3.src= "img/menu3a.gif";


function sel(nom)
{
if (nom>0)
	{
	document["m"+nom].src="img/menu"+nom+"a.gif";
	}
else
	{
	document["m"+(-nom/1)].src="img/menu"+(-nom/1)+"n.gif";
	}
}