var timerRunning = false;
var timerProcess = null;

function timerFunction() { 
    timerRunning = false;
    displaySubmenu (null, "empty", 0);
} 

function startTimer(secs) {
    stopTimer();
    timerProcess = setTimeout('timerFunction()',secs*1000);
    timerRunning = true;
}

function stopTimer() {
    if (timerRunning)
        clearTimeout(timerProcess); 
}

function displaySubmenu(itemObject, listObject, timeout) {
    stopTimer();
    if (document.getElementById) {
        var listElement = null;
        if (listObject != null)
            listElement = document.getElementById(listObject);
        if (listElement == null || listElement.style.display != "block") {
            var listContent = document.getElementById("submenus").getElementsByTagName("div");
            for (var i=0; i<listContent.length; i++) {
                if (listContent[i].className=="submenu") {
                    listContent[i].style.display = "none";
                }
            }
            if (listElement != null)
                listElement.style.display = "block";
        }

        var itemElement = null;
        if (itemObject != null)
            itemElement = document.getElementById(itemObject);
        for (var i=1; i<6; i++) {
            var item = document.getElementById ("nav"+i);
            if (item.className != "navitem") {
                item.className = "navitem";
            }
        }
        if (itemElement != null)
            itemElement.className = "navitem-highlight";
            
        if (timeout > 0)
            startTimer (timeout);
    }
}