判断2个输入框至少输入1个

    <script type="text/javascript">
        function check_input() {
            var name = document.getElementById("txtname");
            var phone = document.getElementById("txtphone");
            if ((name.value.length == 0) && (phone.value.length == 0)) {
                alert("请至少输入一个查询条件");
                return false;
            }
            else
                return true;
  }
</script>



<p>用户姓名：<asp:TextBox ID="txtname" runat="server"></asp:TextBox></p>
         <p>手机号码：<asp:TextBox ID="txtphone" runat="server"></asp:TextBox></p>
        <asp:Button ID="btnsearch" runat="server" Text="查询" CssClass="btn" OnClientClick="return check_input()"
             onclick="btnsearch_Click"/>