startList = function()
{
    if (document.all&&document.getElementById)
    {
        navRoot = document.getElementById("top_nav");
        
        cn=navRoot.childNodes;
        l1=cn.length;
        
        for (i=0; i<l1; i++)
        {
            node = navRoot.childNodes[i];
            
            if (node.nodeName=="LI")
            {
                node.onmouseover=function()
                {
                    this.className+=" over";
                }
                
                node.onmouseout=function()
                {
                    this.className=this.className.replace(" over", "");
                }
            }
        }
    }
}

window.onload=startList;