这样?
    <script language="javascript">
        function test() {
            if (!confirm("确定?")) {
                var tb = document.getElementById("TextBox1");
                tb.value = ""; //清空
                  tb.focus();
                return false;
            }
            return true;
        }
    </script>
     <div>
        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
    </div>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
        ControlToValidate="TextBox1" ErrorMessage="内容不可以为空"></asp:RequiredFieldValidator>
    <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return test()"
        OnClick="Button1_Click" />
    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
        protected void Button1_Click(object sender, EventArgs e)
        {
            if (IsValid)//验证成功
            {
                Label1.Text = "你在" + DateTime.Now.ToString() + "发送命令成功";
            }
        }

解决方案 »

  1.   


    <input type="button" onclick="return confirm('yes or no');" 
    onserverclick="functionName" runat="server">
      

  2.   

    这个简单啊
    验证一下 textbox 中的内容是否为空,如果是空就不弹出确认对话框就 ok!
      

  3.   


    function test() {
              if(document.getElementById('textbox的id').value)
                if (!confirm("确定?")) {
                    var tb = document.getElementById("TextBox1");
                    tb.value = ""; //清空
                      tb.focus();
                    return false;
                }
                return true;
            }
      

  4.   

    <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return confirm('yes or no')        OnClick="Button1_Click" />