// JavaScript per visualizzare o nascondere i relativi menu' a tendina
function getStyleObject(objectId) {
    // cross-browser function to get an object's style object given its id
    if(document.getElementById && document.getElementById(objectId)) {
	// W3C DOM
	return document.getElementById(objectId).style;
    } else if (document.all && document.all(objectId)) {
	// MSIE 4 DOM
	return document.all(objectId).style;
    } else if (document.layers && document.layers[objectId]) {
	// NN 4 DOM.. note: this won't find nested layers
	return document.layers[objectId];
    } else {
	return false;
    }
}

function changeObjectVisibility(objectId, newVisibility) {
    var styleObject = getStyleObject(objectId);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	return false;
    }
}

function showMenu(menuNumber, eventObj) {
    hideAllMenus();
    var menuId = 'menu' + menuNumber;
    if(changeObjectVisibility(menuId, 'visible')) {
	var menuTitle = getStyleObject('menuTitle' + menuNumber);
	eventObj.cancelBubble = true;
	return true;
    } else {
	return false;
    }
}

var numMenus = 9;

function hideAllMenus() {
    for(counter = 1; counter <= numMenus; counter++) {
	changeObjectVisibility('menu' + counter, 'hidden');
	var menuTitle = getStyleObject('menuTitle' + counter);
    }
}

function scriveHTML() {
outPut = '';
// document.write(outPut);
}
document.onclick = hideAllMenus;
scriveHTML();
<!--
function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->