C# / ASP.NET Validate

[LC]

I am building a simple application that delete an item from a database table.
I want to use javascript to popup a confirmation window before the actual
server event is triggered.

i tried to use

button1.Attributes["onclick"] = "javascript:return(window.confirm('Are you
sure to delete?'))";

it seems the that event doesn't fire at all. Anyone have a suggestion??

any way to confirm at the client side before the event fire? I know if I
use a HTML form control, I can manupilate the event.

Thanks.

Leung