function affich_help(page,url,largeur,hauteur,barre) {
	var top=100;
	var left=((screen.width-largeur)/2)-10;
	fen=window.open(url,page,"top="+top+",left="+left+",width="+largeur+",height="+hauteur+",menubar=0,status=0,resizable=0,scrollbars="+barre+",location=0, toolbar=0")
}