验证用户必选CheckBox控件与自定义验证javascript代码

<br>function ValidateCheckBox(sender, args) { <br>var checkbox = document.getElementById("<%=CheckBox1.ClientID %>") <br>if (checkbox.checked) { <br>args.IsValid = true; <br>} <br>else { <br>args.IsValid = false; <br>} <br>} <br> <br><span><u></u></span> 代码如下:<pre class="brush:php;toolbar:false layui-box layui-code-view layui-code-notepad"><ol class="layui-code-ol"><li><br><asp:CheckBox ID="CheckBox1" runat="server" /> <br><asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="必须选择选项" ForeColor="Red" ClientValidationFunction="ValidateCheckBox"></asp:CustomValidator><br /> <br><asp:Button ID="Button1" runat="server" Text="提交" /> <br> <br><strong>演示</strong>：<br><img src="https://img.gxlcms.com//Uploads-s/new/2019-09-19-201919/2013116100611729.gif"></li><li>            </li><li>                                </li></ol></pre>