HTML and CSS Reference
A web server is the program that runs on a computer and is responsible for replying to
web browser requests for files. You need a web server to publish documents on the Web.
One point of confusion is that the computer on which a server program runs is also
referred to as a server. So, when someone uses the term web server , she could be refer-
ring to a program used to distribute web pages or the computer on which that program
When you use a browser to request a page on a website, that browser makes a web con-
nection to a server using HTTP. The server accepts the connection, sends the contents of
the requested files, and then closes the connection. The browser then formats the infor-
mation it got from the server.
On the server side, many different browsers can connect to the same server to get the
same information. The web server is responsible for handling all these requests.
Web servers do more than just serve files. They're also responsible for managing form
input and for linking forms and browsers with programs such as databases running on the
As with browsers, many different servers are available for many different platforms, each
with many different features. For now, all you need to know is what the server is there
for; you'll learn more about web servers in Lesson 20, “Putting Your Site Online.”
These days, a lot of people make websites without uploading pages to a web server. They
publish blogs using any of a number of popular services, or they use a content manage-
ment system of some kind, or they publish pages on a wiki. Even using Twitter and post-
ing status updates on Facebook are forms of web publishing. Regardless of the
application you use to publish information on the Web, it is likely to be published as
HTML, and understanding how HTML works can help you achieve the results you
As you learned earlier, a URL is a pointer to some bit of data on the Web, be it a web
document, a file available via FTP, a posting on Usenet, or an email address. The URL
provides a universal, consistent method for finding and accessing information.
In addition to typing URLs directly into your browser to go to a particular page, you also
use URLs when you create a hypertext link within a document to another document. So,
any way you look at it, URLs are important to how you and your browser get around on