Local disk C contents

As a joke, some people have on their homepages an indication that they can see other people’s C drive contents. I think the term is “file:///C:/”
An example is near the bottom of this person’s homepage:
There is a box that says “Click Me.” Hows does this work? And is there a way a person could really see the drive contents of others? I thought this was posted here before but couldn’t find it. Thanks!

All that happens when you click that button is that you browse your own C: drive. The owner of the web page isn’t seeing anything. The web browser is merely looking “inwards” at your own files; no information is being sent externally as far as I can tell.

If you select ‘open file’ for a text file with your browser, notice the url it gives? It just a link
to your local HD. Most people have Notepad in the same location on their HD so a link
to it on the web opens it on most computers. Frankly, I don’t think people should make
web pages that do this.