6 Some basic terms
Here are the parts of a URL considered more closely.
Note: it's not essential to remember everything you'll find in this
chapter. Just read it through so that you'll know where to find the information
if it's needed.
In Chapter 3 'Web page and website'
there appeared the following URL:
Let's study more closely what the parts of this string indicate.
The parts of the URL:
http Protocol used in the communication between the browser and the web
a set of rules a browser and a web server use to communicate with and
understand each other.
: Colon simply separates the protocol from the other part of the web address.
// Indicates that a contact to a
server is to be achieved. (For example, when sending email the notation
'mailto:<email address>...', without slashes, could be used). Note that
this doesn't mean a connection
between a browser and server. When a browser has sent a request, there is no connection between the browser and the
server. (You can read more about how the web actually works here.)
www Name of
a server listening to messages using the http protocol.
Note that this name is not always shown in the URL in the Location Box. And the
name can be something other than 'www'.
nypl.org Name of the domain where the web server belongs.
Domain is like an address by which you can get to some specific 'area' on the
Net. For example, the domain name 'nypl.org'
is registered to The New York Public Library and
there are probably several server programs in that domain each dedicated to
This part of
the URL is actually the name of the
web server seen over the Internet. In other words, it's the server that
hosts the web site of The New York Public Library. By using it the request a browser sends can be
directed to the right web server.
You may wonder
how a request can be directed to the right server if the name is not shown in
the URL. In fact, the sequence is such that a request is first directed to the
domain and then in the domain the right server is found. In the domain an http
request goes to the server that is listening to messages using the http
/ Indicates the root folder
of the folder system hosted by
the web server www.nypl.org.
sitemap/ Indicates a folder in the root folder.
index.html The name of
the document file requested.
Note that though there is a URL seen on the Location Box, the browser
doesn't have a direct connection to a
folder and a document file there on the disk of the server machine. It is
always the web server that fetches
the document and sends it to the
browser. So nothing can be 'disturbed' on a web server by using a browser.
In folders hosted by a web server there is usually a file which is
returned in case only the name of the folder is given. (For example, you can
try what happens when you type 'nypl.org/sitemap/'
on the Location Box and press Enter.)
This specific default page can be named in several ways:
name doesn't make a difference; a default page is shown if no other file is
mentioned after the name of a folder.
You can study these things yourself by
trying different URLs.
some occasions this chapter may be helpful. For example, if you
to give somebody a URL for a certain file, it's good to know
a correct URL must contain.