dropdownlist超链接问题

<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"  onselectedindexchanged="DropDownList1_SelectedIndexChanged">
            <asp:ListItem Selected="True">请选择</asp:ListItem>
            <asp:ListItem Value="http://www.baidu.com">sina</asp:ListItem>
            <asp:ListItem Value="http://www.sohu.com"></asp:ListItem>
            <asp:ListItem Value="http://www.163.com">163</asp:ListItem>
        </asp:DropDownList></div>
    </form>
</body>
怎么在dropdownlist下拉框里选sina；163等在新的页面打开啊，请高手指教，写出具体的代码，
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"  onselectedindexchanged="DropDownList1_SelectedIndexChanged">
            <asp:ListItem Selected="True">请选择</asp:ListItem>
            <asp:ListItem Value="http://www.baidu.com">sina</asp:ListItem>
            <asp:ListItem Value="http://www.sohu.com"></asp:ListItem>
            <asp:ListItem Value="http://www.163.com">163</asp:ListItem>
        </asp:DropDownList></div>
    </form>
</body>
怎么在dropdownlist下拉框里选sina；163等,并在新的页面打开啊，请高手指教，写出具体的代码.小弟乃初级新手，