列表页面导航栏链接点击后变色

 后台

       int id = int.Parse(Request.QueryString["id"].ToString());
        switch(id)
        {
            case 1:
                Image1.ImageUrl = "/images/research_pic.gif";
                Image2.ImageUrl = "/images/research.gif";
                list1.Attributes["class"] = "nav04_live";
                Page.Title = "森明研究";
                break;
            case 2:
                Image1.ImageUrl = "/images/trade_pic.gif";
                Image2.ImageUrl = "/images/trade.gif";
                list2.Attributes["class"] = "nav05_live";
                Page.Title = "行业动态";
                break;
            default:
                Image1.ImageUrl = "/images/policy_pic.gif";
                Image2.ImageUrl = "/images/policy.gif";
                list3.Attributes["class"] = "nav06_live";
                Page.Title = "政策法规";
                break;
        }

前台

<li class="nav04" id="list1" runat="server" ><a href="/NewsList.aspx?id=1">森明研究 </a></li>
<li class="nav05" id="list2" runat="server"  ><a href="/NewsList.aspx?id=2">行业动态</a></li>
<li class="nav06" id="list3" runat="server" ><a href="/NewsList.aspx?id=3">政策法规</a></li>