Desabilitar função de clique..

Gente.. to com um código aqui que ele funciona certinho.. é um código de menu drop down.. quando você passa o mouse em cima ele abre os sub menu..

Porém para desativar você tem que clicar em algum lugar na tela...

Como deixo ele para desativar o sub menu quando tirar o mouse..

Abaixo um trecho do código onde configura as funções dele :

<script type="text/javascript">
function Browser() {

 this.isIE	= false; // Internet Explorer
 this.isOP	= false; // Opera
 this.isNS	= false; // Netscape
 this.version = null;

 var ua= navigator.userAgent, s, i;
 s = "Opera";
 if ((i = ua.indexOf(s)) >= 0) {
	this.isOP = true;
	this.version = parseFloat(ua.substr(i + s.length));
	return;
 }

 s = "Netscape6/";
 if ((i = ua.indexOf(s)) >= 0) {
	this.isNS = true;
	this.version = parseFloat(ua.substr(i + s.length));
	return;
 }

 // Treat any other "Gecko" browser as Netscape 6.1.
 s = "Gecko";
 if ((i = ua.indexOf(s)) >= 0) {
	this.isNS = true;
	this.version = 6.1;
	return;
 }

 s = "MSIE";
 if ((i = ua.indexOf(s))) {
	this.isIE = true;
	this.version = parseFloat(ua.substr(i + s.length));
	return;
 }
}

var browser = new Browser();

//----------------------------------------------------------------------------
// Code for handling the menu bar and active button.
//----------------------------------------------------------------------------

var activeButton = null;

// Capture mouse clicks on the page so any active button can be
// deactivated.

if (browser.isIE)
 document.onmousedown = pageMousedown;

 document.addEventListener("mousedown", pageMousedown, true);

function pageMousedown(event) {
 if (activeButton == null) return;
 var el;
 if (browser.isIE)
	el = window.event.srcElement;
 else
	el = (event.target.tagName ? event.target : event.target.parentNode);

 // If the active button was clicked on, exit.
 if (el == activeButton) return;

 // If the element is not part of a menu, reset and clear the active
 // button.
 if (getContainerWith(el, "DIV", "menu") == null) {
	resetButton(activeButton);
	activeButton = null;
 }
}

function buttonClick(event, menuId) {
 var button;
 if (browser.isIE)
	button = window.event.srcElement;
 else
	button = event.currentTarget;

 // remove the thin white line.
 button.blur();

 if (button.menu == null) {
	button.menu = document.getElementById(menuId);
	if (button.menu.isInitialized == null)
 menuInit(button.menu);
 }

 // Reset the currently active button, if any.
 if (activeButton != null)
	resetButton(activeButton);

 // Activate this button, unless it was the currently active one.
 if (button != activeButton) {
	depressButton(button);
	activeButton = button;
 }
 else
	activeButton = null;
 return false;
}

function buttonMouseover(event, menuId) {
 var button;
 if (browser.isIE)
	button = window.event.srcElement;
 else
	button = event.currentTarget;

 // If any other button menu is active, make this one active instead.
 if (activeButton != null && activeButton != button)
	buttonClick(event, menuId);
}

function depressButton(button) {
 var x = getPageOffsetLeft(button);
 var y = getPageOffsetTop(button) + button.offsetHeight;

 // For IE, adjust position.
 if (browser.isIE) {
	x += button.offsetParent.clientLeft;
	y += button.offsetParent.clientTop;
 }

 button.className += " menuButtonActive";
 button.menu.style.left = x + "px";
 button.menu.style.top = y + "px";
 button.menu.style.visibility = "visible";
}

function resetButton(button) {
 removeClassName(button, "menuButtonActive");
 if (button.menu != null) {
	closeSubMenu(button.menu);
	button.menu.style.visibility = "hidden";
 }
}