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Absolute Path URLs
URLs can be either absolute or relative. An absolute URL shows
the entire path to the file, including the scheme, server name,
the complete path, and the file name itself . An
absolute URL is analogous to a complete street address, including
name, street and number, city, state, zip code, and country.
No matter where a letter is sent from, the post office will be
able to find the recipient. In terms of URLs, this means that
the location of the absolute URL itself has no bearing on the
location of the actual file referenced—whether it is in
a Web page on your server or on mine, an absolute URL will look
exactly the same.
A URL with a trailing forward slash and no file
name points to the default file in the last directory named (in
this case the liz directory). Some common default file names are
index.html and default.htm.
Relative Path URLs
To give directions to your
neighbor's house, instead of giving the complete address, you might
just say "it's
four doors down on the left". This is a relative address—where
it points to depends on you start.
With the same information in a different city, someone would
never find your neighbor.
The relative URL for a file in the same folder as the file that
contains the link is just the file's name and extension.
In the same way, a relative URL describes the location of the
desired file with reference to the location of the file that contains
the
URL itself. So, you might
have the URL say something like "show the xyz image that's in the same directory
as the current file".
For a file that is within a folder inside the current
folder, add the folder's name and a forward slash
in front of the file
name.
In this case, the relative URL for a file that
is in the same directory as the current file (that is, the one
containing the URL in question) is simply
the
file name
and extension. You create the URL for a file in a subdirectory
of the current directory with the name of the subdirectory followed by a
forward slash and then the name and extension of the desired file.
This file is in
a folder that is inside the folder that contains the current folder.
In that case, you use two periods and a slash to go up a level,
and then note the subdirectory, followed by a forward
slash, followed by the file name.
To reference a file in a directory at a higher level
of the file hierarchy, use two periods and a forward slash. You
can combine and repeat the two periods and forward slash to reference
any file on the same hard disk as the current file.
Generally, you should always use relative URLs.
They're much easier to type and they make it easy to move your
pages from a local system
to a server—as long as the relative position of each file
remains constant, the links will work correctly.
One added advantage of relative URLs is that you don't have to
type the scheme-as long as it's HTTP.
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