function launchVirtualVisit(url){
	h=400;
	l=600;
	hauteur=Math.round((screen.availHeight-h)/2);
	largeur=Math.round((screen.availWidth-l)/2);
	fen = window.open(url, "virtualVisit", "toolbar=0,location=0,directories=0,status=0,scrollbars=1, resizable=1,menubar=0,top="+hauteur+",left="+largeur+",width="+l+",height="+h);
	fen.focus();
}