TODO:
You are using a Telerik RadButton, and you want to display a Confirm Dialog, and capture the user pressing cancel, thus canceling the Postback.
SOLUTION:
<!-- Define button, and put method to call in the OnClientClicking event -->
<telerik:RadButtonID="btnDelete"runat="server"Text="Delete Customer"OnClick="btnDelete_Click"
OnClientClicking="ConfirmDelete">
</telerik:RadButton>
<!-- Confirm action here. Cancel press in this dialog will return FALSE, which in turn we will catch and set cancel = true in the args -->
<telerik:RadCodeBlockID="RadCodeBlock1"runat="server">
<scripttype="text/javascript">
function ConfirmDelete(sender, args) {
if (!confirm('Delete Customer, do you wish to proceed?')) {
args.set_cancel(true);
}
}
</script>
</telerik:RadCodeBlock>
NOTES:
You may not need the RadCodeBlock, I did in this case due to Application