function MM_findObj(n, d) { //v4.0
	var p,i,x;
	if(!d) d=document;
	if((p=n.indexOf("?"))>0&&parent.frames.length) {
		d=parent.frames[n.substring(p+1)].document;
		n=n.substring(0,p);
	}
	if(!(x=d[n])&&d.all) x=d.all[n];
	for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  	for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  	if(!x && document.getElementById) x=document.getElementById(n); return x;
}

function activerLayer(couche, boolValue) {
	if (!(layer = MM_findObj(couche))) return;
	if (boolValue==true)
	{
	  if (layer.style.visibility != 'visible')
	    layer.style.visibility = 'visible';
	}
	else
	  layer.style.visibility = 'hidden';
}