function afficher(item1, item2) {
	var div = document.getElementById(item1);
	var img = document.getElementById(item2);
	if (div.style.display == "none"){
	  div.style.display = "";
	  img.src = "images/moins.jpg";
	}
	else {
	  div.style.display = "none";
	  img.src = "images/plus.jpg";
	}
}