You can have a look at this article that show you a technique for creating a buffered upload
Dime Buffered Upload[
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However, pay attention to one of the questions in the forum 'Can I use this in a web application'
'the simple answer is no, and you need to understand that a web browser will never offer advanced file IO to the client file system. have a read of the other comments if you need more explanation.'
In a browser application, when you choose to upload a file, you only get a choice of where the file is located and then it is sent as an HTTP Post to the server. As explained in that answer, you won't have the opportunity to split a file and send in chunks.
However, you could implement some sort of client service that the browser communicates with, then have the service perform the buffered upload. I think there are some flash components that let you do something along these lines?
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