function change_class(idElement) {
	var btn = document.getElementById(idElement);
	switch (idElement){
		case "haut1":
			if (btn.className == "haut1_on")
				btn.className= "haut1";
			else
				btn.className= "haut1_on";
			break;
		case "haut2":
			if (btn.className == "haut2_on")
				btn.className= "haut2";
			else
				btn.className= "haut2_on";
			break;
		case "haut3":
			if (btn.className == "haut3_on")
				btn.className= "haut3";
			else
				btn.className= "haut3_on";
			break;
	}
}