Partial URLs
In some cases, it may be possible to omit a portion of the URL, if the information being left out either does not apply in the particular case, or if the missing information can be "filled in" by default.
There are several reasons this might happen:
Implied Server
The server may already be configured locally, as a preferences setting of the browser. This happens with Usenet news and electronic mail servers. So the URL consists of just a protocol and a resource id:news:news.group
mailto:user@lehigh.eduNotice that the double slash, "//", which normally follows the colon, is missing.
Implied Resource
If you access a site without specifying a particular resource, there may be a default (the URL for the Lehigh homepage, shown below, is an example of this; the actual file is named "welcome.html.") Also, if you specify only a directory (the URL ends in a slash, "/"), the server will look for a file called "index.html," and if it does not exist, will create it "on-the-fly" based on the contents of that directory:http://www.lehigh.edu/
http://www.fake.com/somedir/
Implied Protocol and/or Path
If you are linking from one web document to another one on the same server (especially if it is in the same directory as the document being linked from), you may be able to omit the protocol and server id:next-file.html
/topdir/subdir/another-file.html
/~alias/subdir/another-file.html
SDR, 11 Jun 1995.