Hi,
You can do it in both Client Side & Server Side.
Client Side using JavaScript
<asp:checkbox id="CheckBoxID" runat="server" onclick="CheckBoxChecked(this)" xmlns:asp="#unknown" />
function CheckBoxChecked(value) {
if(value.checked == true)
document.getElementById("<%=LabelId.ClientID %>").style.display = 'none';
else
document.getElementById("<%=LabelId.ClientID %>").style.display = 'block' ;
}
Server Side Event
<asp:checkbox id="CheckBoxID" runat="server" oncheckedchanged="CheckBoxChanged" xmlns:asp="#unknown" />
void CheckBoxChanged(object sender, EventArgs e)
{
LabelID.Visible = false;
}
Happy Coding :)