How to create confirmation box at server side?

[Suresh K]

Hi

             I am uploading files to server from webpage. Here I am checking whether file exist or not in server if exist I would like to ask Confirmation message like ‘File already Exist on Server, do you want to Override, if YES I want to Override, if NO  I want to skip that file and go for next file.

Here I am using Telerik:RadUpload control to upload multiple files.

Can you please help me to solve this issue.