HTML and CSS Reference
the Web is self-documenting. Information about what is on the Web, how it is
organized, and how it can be used is everywhere on the Web.
Content is everything. Online, it is HTML markup that tells your browser what
that content means and how to present it to you. he concept of markup comes
from traditional print publishing, in which a writer supplies the content,
which an editor then marks up with instructions for the printer, specifying the
layout and typography of the work. he printer, following the markup, type-
sets the pages and reproduces copies for distribution.
With the Web and HTML, the author and the editor are oten the same per-
son. he work, or content, lives in a linked set of HTML iles on a web server.
he content is not distributed in discrete copies, as in the print publication
model. Instead, copies of web pages are served in response to user requests.
he information returned by the web server is processed by the user's browser
to display a web page in a window or tab.
Oten the content of a web page does not reside in an HTML ile but is gen-
erated dynamically by the web server from information stored in a database,
using templates to produce web pages . It is common for web page to encom-
pass resources from other servers. hat is, a request a browser sends to a web
server may result in that web server making requests of other servers. hese
distinctions, however, are immaterial to the user's browser. It just downloads
whatever the web server provides without caring how that content was created
or who marked it up.
he technological concepts are simple: an open exchange of data and infor-
mation about that data (metadata), including content and markup. As a con-
nected world of places to visit, the Web is more than a metaphor. he language
of the Web, including verbs such as surf , browse , visit , search , explore , and
navigate , and nouns such as site , home page , destination , gateway , and forum ,
creates a very real experience of being someplace.
How does a browser know what to request of a web server? How does your
browser know which web server, of the millions in the world, to ask? he
answer, as you've probably guessed, is links! A link is a reference, embedded in
the content of a document, to another resource on the Web. his is the essence
of hypertext media.