HTML document
Going Online
Chapter 7
Computers: Information Technology in Perspective
By Long and Long
Copyright 2002 Prentice Hall, Inc.
2012 Jaana Holvikivi
7.2
What Is the Internet?
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The Net is a worldwide collection of interconnected networks.
7.3
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ARPANET
1969-1994
Internet
InterNIC
W3C
Internet History
http://www.cybergeography.org/atlas/historical.html
http://websearch.about.com/od/searchingtheweb/a/webhistory
.htm
Internet
No person or organization governs the Internet!
7.4
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Submarine cables
For a recent image see: http://www.telegeography.com/assets/website/images/maps/submarine-cable-map-2011/submarine-cable-map-2011-x.jpg
7.5
Quit http://arstechnica.com/business/2012/05/bandwidthexplosion-as-internet-use-soars-can-bottlenecks-beaverted/
May 1, 2012
7.6
Reliance on cloud services
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Amazon cloud down; Reddit, Github, other major sites affected http://www.zdnet.com/amazon-cloud-down-reddit-github-othermajor-sites-affected-7000006166/
Google down: http://edition.cnn.com/2013/07/10/tech/web/google-down
7.7
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How do you get on?
Via dial-up/ ADSL connection to
Information Service Gateway
Telecommunications company
Internet Service Provider
(ISP)
Via direct network connection using a shared high-speed line on LAN or WLAN
7.8
Internet Terminology
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Transmission Control Protocol/ Internet
Protocol (TCP/IP)
Packets: transmission is split and packets could take different routes
IP addresses
195.148.144.23
every machine has an address dynamic IP addresses; sub-networks
Extension of address space IPv6 official on 1 June 2012
7.9
Retrieve/View Internet Information
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Client/server programs
Browsers
Internet Explorer
Firefox, Safari, Chrome
The Internet address (URL)
Identifies location of server site
Files are downloaded for viewing
7.10
Uniform Resource Locator
Quit http://www.prenhall.com/long/9e/main.html
Access
Method
Or
Protocol
Domain
Name Directory Filename
7.11
URL: Access Methods
Quit http:// Hypertext Transport Protocol https:// secure Hypertext Transport Protocol ftp:// File Transfer Protocol
XMPP chat protocol gopher:// Gopher menu tree
7.12
URL: Top-Level Domains (TLDs)
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ID
.com
.edu
.firm
.gov
.int
.mil
.net
.org
.info
Affiliation
Commercial
Education US
Businesses
Government US
International
Military US
Network Resources
Nonprofit Organizations
7.13
URL: Top-Level Domains (TLDs)
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ID
.fi
.ca
.uk
.ru
.tv
.de
.cn
.za
Countries
Finland
Canada
UK
Russia
Tuvalu
Germany
China
South Africa
Extension could be anything!
HTML: Basic structure
<html>
<head>
<title> A sample HTML document </title>
</head>
<body>
<p>
This is a sample HTML document
</p>
</body>
</html>
<html>
<head>
<title> A sample HTML document </title>
</head>
<body>
<h1> HTML document </h1>
<p>
This is a sample HTML document
</p>
<hr/>
<p>Created by JHH in 2012 </p>
</body>
</html>
Important HTML - elements link:
< a href="http://www.google.com" > Search engine </ a >
Start, close element space attribute="value" image:
< img src="pete.jpg" /> empty element
Space stripped (breaks, tabs, enter)
7.17
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<table>
<tr>
<td> cell1 </td>
<td> cell 2 </td>
</tr>
<tr>
<td> < img src="photo.gif" /> </td>
<td> 1 </td>
</tr>
</table>
Symmetrical structure!!
Tables
7.18
HTML document contents
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Every HTML document should contain certain basic information about its origin :
The author of the document, and the person who is formally in charge of the document.
The date of creation of the document, or the date of last update, or both.
The context of the document and its status , part of official documentation by a company about one of its products, or part of a private person's information.
Page requests on the Web
Browser:
HTML, scripts
User workstation
HTTP request
HTTP: HTML pages
Internet
Server
HTML pages
Program Server
CGI PHP
Database server
ASP Java
SQL
Oracle
HTTP requests
GET /index.html HTTP/1.1
Host: www.evtek.fi
Accept: www/source
Accept: text/html
Accept: image/gif
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 a blank line *
The client lists the Multipurpose Internet Mail
Extension (MIME) types it will accept in return.
Finally, the client sends a blank line indicating it has completed its request.
HTTP server response
HTTP/1.1 200 OK
Date: Mon, 09 Apr 2007 12:39:22 GMT
Server: Apache/1.3.27 (Unix) (Red-Hat/Linux)
Set-Cookie: fe_typo_user=4f74f6c85b; path=/; domain=www.evtek.fi
Last-Modified: Wed, 08 Jan 2007 23:11:55 GMT
Etag: "3f80f-1b6-3e1cb03b"
Accept-Ranges: bytes
Content-Length: 438
Connection: close
Content-Type: text/html; charset=UTF-8
GET and POST methods
The difference between these two methods is in the way of sending data to the page:
GET method sends data using URL (size limit),
<form method="GET" action="prog2.html"> http://www.google.com/search?sourceid=gmail&q=get%20m ethod
POST method sends data through a standard entrance
<form method="post" action="http://www.school.fi/cgibin/post-query">
Creating and sending home pages
Local disk
Windows OS
D:\documents index.html
picture1.jpg
logo2.gif
page2.html
FTP, SHH
Server disk
Linux or Unix OS http://users.metropolia.fi
Home directory of user x
• public_html index.html
picture1.jpg
logo2.gif
page2.html
•Mail and other data
Workstation
Local use: editing
Remote use through internet: visiting Web pages
7.24
Quit president@whitehouse.gov
bsmith@abccorporation.com
Username@domain or email server
To
CC: and/or BCC:)
Subject
Message
Attached file(s)
The e-mail message
Reply
Reply to all
Forward
E-mail response options
Telecommuting
Post Office Protocol
synchronization of mails
7.25
Open and shared information
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social media
Blogs
Commercials sites include user ratings and forums (hotel comparison, shops, Amazon)
Google: maps, images, applications
Open Data
use of information
7.26
Cloud
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Amazon EC2: server space
Dropbox
SAAS software as service, pay as you use
Youtube, Skype, Twitter
Facebook, Linkedin, Google+
Risks, fast evolving
