验证用户必选CheckBox控件与自定义验证javascript代码

function ValidateCheckBox(sender, args) { 
var checkbox = document.getElementById("<%=CheckBox1.ClientID %>") 
if (checkbox.checked) { 
args.IsValid = true; 
} 
else { 
args.IsValid = false; 
} 
} 
 
 代码如下:

<asp:CheckBox ID="CheckBox1" runat="server" /> 
<asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="必须选择选项" ForeColor="Red" ClientValidationFunction="ValidateCheckBox"></asp:CustomValidator><br /> 
<asp:Button ID="Button1" runat="server" Text="提交" /> 
 
演示：