I don't know if this is possible or not, but here is what I'm envisioning.
I have a asp.net button ("Save button"), the user clicks it, which of course fires the Server side OnClick event.  While going through the OnClick code, if it meets a specific criteria it does a "Confirmation" popup on the clients screen.  Depending on which button the client clicks ("YES"/"NO") in the confirmation popup it will either continue or exit the "OnClick" event.  If I'm understanding on how ASP.Net works this will cause a 2nd PostBack to get the "Confirmation Popup "Yes" or "No" back to the server, this will cause the loss of the data I am attempting to save.
Is this possible and if so then how?

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