File URLs

http://en.wikipedia.org/wiki/File_URI_scheme
http://kb.mozillazine.org/Firefox_:_Issues_:_Links_to_Local_Pages_Don%27t_Work#LocalLink
http://www.w3schools.com/HTML/html_url.asp

http://www.cs.tut.fi/~jkorpela/fileurl.html
File URLs

One of the possible forms of a URL is a file URL, which is of the form

file://host/path

Thus, you can hardly expect a file URL to work on the Web except locally, when the host referred to is the same on which one uses a Web browser. The special name localhost or omission of the host name (e.g., file://localhost/foo or file:///foo) can be used to specify such a reference. Notice that if you have, say, the file://localhost/C|/NETLOG.TXT URL in a link on your Web page, then a person following that link will either see an error message or the content of his own NETLOG.TXT file!