简单的Javascript 查找子元素

代码如下：

    <script language="javascript" type="text/javascript">
        function startList() 
        {
            if (document.all&&document.getElementById) 
            {
                var navRoot = document.getElementById("nav");
                for (i=0; i<navRoot.childNodes.length; 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;
    </script>

谢谢浏览！