var iTimeout = 500;
var cTimer = null;
var cCurrentMenu = null;

function OpenMenu(id)
{	
    CancelCloseTimer();

	if(cCurrentMenu != null)
        CloseMenu();

	cCurrentMenu = document.getElementById(id);
	cCurrentMenu.style.visibility = 'visible';

}

function CloseMenu()
{
	if(cCurrentMenu != null) 
    {        
        cCurrentMenu.style.visibility = 'hidden';
        cCurrentMenu = null;
    }
}

function StartCloseTimer()
{
	cTimer = window.setTimeout(CloseMenu, iTimeout);
}

function CancelCloseTimer()
{
	if(cTimer != null)
	{
		window.clearTimeout(cTimer);
		cTimer = null;
	}
}

document.onclick = CloseMenu;