Transcript Introduction_to_Internet

Introduction to the World
Wide Web & Internet
CIS 101
WWW & Internet
1960s – ARPANET conceived as
communication infrastructure for
researchers to share access to
supercomputers
1970s – Universities & research
organizations around the world used
ARPANET
WWW & Internet
1971 – File Transfer Protocol (FTP) allows
users to copy from & to FTP server
machines
1980 – TCP/IP was formalized
1991 – First Web browser & server
1993 – 50 servers on the Web
1993 – Web accounted for 1% of traffic
1990s – Web accounted for 75% of traffic
WWW & Internet
Web browsers, which provided a simple
graphical user interface, had increased
usage
FTP was a more complex line-command
interface
WWW & Internet
3 Components of the Web
1. Uniform Resource Identifier (URI)
2. HTML (HyperText Markup Language)
3. HTTP (HyperText Transport Protocol)
WWW & Internet
1. Uniform Resource Identifier (URI)
Denotes location of a resource
3 Parts
a) Protocol for communicating with server
(http:)
b) Name of server (e.g. www.cnn.com)
c) Name of resource (e.g. picture1.gif)
URLs are the most common URIs
WWW & Internet
2. HTML (HyperText Markup Language)
Allows authors to format text, reference images
and embed links to other documents
WWW & Internet
HTML is a language used to design Web
pages for the Internet
HTML documents are displayed by
means of a Web browser
The browser interprets HTML and
renders it
WWW & Internet
HTML has gone through several
versions, each of which expands the
capabilities of HTML
The most recent version of HTML is
HTML 4.01
WWW & Internet
Dynamic HTML (DHTML) is a term that
describes a combination of HTML tags,
cascading style sheets (CSS), and a
scripting language such as JavaScript.
DHTML allows users to create
interactive, animated Web pages
WWW & Internet
Extensible Markup Language (XML) is a
markup language that uses tags to
describe the structure and content of a
document, not the format
Extensible Hypertext Markup Language
(XHTML) is a reformulation of HTML so it
conforms to Extensible Markup
Language (XML) rules
WWW & Internet
Some HTML Editors
Microsoft Word
Microsoft FrontPage
Internet Explorer
Netscape Navigator
WWW & Internet
HTML Tags
Tags are instructions that HTML uses to
tell the Web browser how to display text,
images and other media
Tags are enclosed in brackets
Most tags have a start tag and an end
tag
WWW & Internet
HTML versus JavaScript
HTML is static
JavaScript allows Web pages to be
dynamic
JavaScript is a language that was
developed strictly for use on the Web
JavaScript can handle calculations,
controls and validate forms with minimal
programming effort
WWW & Internet
JavaScript
It is interactive, i.e. responds to the user
Like HTML it uses open and close tags
WWW & Internet
3. HTTP (HyperText Transport Protocol)
Allows Web components to communicate
e.g. Client & Server
Used to transfer HTML documents of the World
Wide Web
Web Development
WWW & Internet
What is the Internet?
The international computer network of networks
that connect government, academic and
business institutions.
What is the World Wide Web?
A network of servers (computers that handle
requests for data) linked together by a common
protocol (set of rules/standards), allowing access
to millions of hypertext resources (linked
documents).