Even i'm setting args.IsValid=false, form getting submitted
.aspx
<asp:CheckBox ID="CheckBox1" runat="server" />
<asp:CustomValidator ID="CustomValidator1" ClientValidationFunction="cbxvalidate"
runat="server" ErrorMessage="*"></asp:CustomValidator>
java script
function cbxvalidate(sender, args) {
if (document.getElementById('CheckBox1').checked == true) {
args.IsValid = 'true';
} else {
args.IsValid = 'false';
}
}