Accessing local files?

Ok, being a web develper i know that this isnt generally acceptable, and rightly so for many reasons.

But at the moment i am toying with an idea and i basically i want to have a page where when loaded by a client, it (by either asking and getting permission, because the client will WANT to give permission) look for a specific directory on the users computer and read a file within, no writing, no modifying, just read a file.

Ive read recently that HTML5 gives local file storage/access but from what i have read this allocates you space on the HD to store and read files you have put there, so not access to the client directories.

Like i said, i can fully see the reason for not, but the client will want to give permission, so even if there is a promt that is fine.

Thanks
Andy

How often does the file need to be read?
How often does the file contents change?
And what does the file contain that can be read?

I'm thinking that there would be an .exe script running on
the user's PC that periodically uploads (FTP) an XML file or
something containing the data to a website ... to be
read online from the webhost server, not the user's PC.

How about:

<iframe src="directoryName/FileName">
Your browser doesn't support IFrames.
</iframe>

You might also care about things like:

frameborder="1"
width="30%"
height="300"

as far as I know the closest thing to what you want to accomplish would be automated AJAX upload, but user will still have to sellect the file.
that's security measure in all browsers i know.

as far as i know your only option would be to have dedicated software on client's side. For example you can tell your user to download some simple VBasic script to uplaoda files to your server.