CHAPTER 6. USING EXTERNAL RESOURCES 63
name and a path. The domain name is used to find the document root. The
path is used to find a file within that document tree.
If our URL ishttp://example.com/a/b/c/d.htmlthe webhost will split
that into two parts:
Domain:example.com
Path:a/b/c/d.html
For the domain, the webhost will remember the document root. Maybe it
is something like this:
Document root:/home/example/public_html
The server replaces the domain name with the document root, resulting in
this actual filename:
/home/example/public_html/a/b/c/d.html
Exam Question 105(p.342): Is the domain name within a URL case-
sensitive?
Required Answer:no
Exam Question 106(p.342): Is the path within a URL case-sensitive?
Required Answer:yes
6.4 URLs
A fully-complete URL is absolute. It consists of a scheme, such as http, a
domain name, such as example.com, and a path, such as folder/index.html.
It would look like this:
http://example.com/folder/index.html
This is called anabsolute URL, or an absolute address.
HTML allows you to leave out parts of the URL, thus making the URL less
absolute and more relative.
Actually, a fully-specified URL has even more parts, including the query
and the port number, but we will ignore them here.