function menu(lien) {
	body_id = document.getElementsByTagName("body")[0].id;
	lien_class = lien.className;
	ss_menu = lien.getElementsByTagName("ul")[0];
	if( ss_menu.style.visibility != "visible" ){
		ss_menu.style.visibility = "visible";
	}
	else {
		ss_menu.style.visibility = "hidden";
	}
	if ( body_id == lien_class ) {
		ss_menu.style.visibility = "visible";
	}
}

function init() {
	liste_menu = document.getElementById("entete");
	for (var i=0; i<liste_menu.getElementsByTagName("li").length; i++ ) {
		lien_ss_menu = liste_menu.getElementsByTagName("li")[i];
		if ( lien_ss_menu.getElementsByTagName("ul")[0] ) {
			lien_ss_menu.onmouseover = function () { menu(this) };			
			lien_ss_menu.onmouseout = function () { menu(this) };			
		}
	}
}
window.onload = init;