var treeMenu = new Object();

treeMenu.buildTree = function(treeId)
{
    var ulList = document.getElementById(treeId).getElementsByTagName('ul');
    for (var i = 0; i < ulList.length; i++)
    {
        treeMenu.buildSubTree(treeId, ulList[i], i);
    }
}
treeMenu.buildSubTree = function(treeId, ulElement, index)
{
    ulElement.parentNode.className = "submenu";
    ulElement.setAttribute('rel', 'closed');
    ulElement.style.display = 'none';
    ulElement.parentNode.onclick = function(e)
    {
        var subMenu = this.getElementsByTagName('ul')[0];
        if (subMenu.getAttribute('rel') == 'closed')
        {
            subMenu.style.display = 'block';
            subMenu.setAttribute('rel', 'open');
        }
        else
        {
            subMenu.style.display = 'none';
            subMenu.setAttribute('rel', 'closed');
        }
        treeMenu.preventPropagation(e);
    }
    ulElement.onclick = function(e)
    {
        treeMenu.preventPropagation(e);
    }
}
treeMenu.preventPropagation = function(e)
{
    if (typeof e != "undefined")
    {
        e.stopPropagation();
    }
    else
    {
        event.cancelBubble = true;
    }
}