Web Development Slides

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Transcript Web Development Slides 

Delving into the Internet and Networks
In the beginning
ARPANET – set up for the military to
have another network of communication
 Pre-cursor to the internet

HTML
Hyper Text Markup Language
 Displayed through a web browser
 Is being replaced by XHTML

XHTML
Extensive Hyper Text Markup Language
 More specific than HTML
 Used to allow for XML
 XML is used to create your own tags

Doctype
Strict
 Transitional
 Frameset

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
CSS
Cascading Style Sheet
 Internal or linked
 Control the appearance of elements in
your web page.
 Why cascading?

JavaScript
Must activate in Internet Explorer
 Used with forms for processing
information
 Used with CSS to animate elements

Cookies
Text file
 Saved on YOUR computer
 Used to help keep setting at a website
 Expiration Date

DOM

Document Object Model
Flash
Good for animations
 Creates a .swf file
 Can have anchors/links
 Embedded into an HTML file
 Text in Flash movies not searchable

File Types

Files made up of a filename and a file
extension separated by a period
myreport.doc
banner.jpg
index.html
file name
file extension
Webpage files
use the following extensions
 .html
 .htm
 .php
 .asp
 .jsp

Graphic Files
Use the
following
extensions

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
.jpg
.gif
.png
.tiff
.bmp
File attributes
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Compressed, basic graphics
Compressed, support transparency and
animation
Compressed, more colors, alpha channel
Not compressed, must have application to
view it
Not compressed, basic image, MS Paint’s
default
Other files
.exe – executable files
 .pdf – acrobat reader
 .doc – word document
 .css – cascading style sheet
 .js – javascript file

Multimedia Files
MPEG – Graphics and Sound
 .avi – video
 .mov – quicktime movie
 .swf - flash movie

Compression Files

Some graphic files are compressed:
 jpg, gif, png

Other compressions
 zip (archive)
Protocols

What is a protocol?
 Just a standard way to do something
 Ex: US mail address follows a protocol
○ Persons Name
○ Street Address
○ City, State, and Zip Code

The internet uses certain protocols for
transferring electronic data
HTTP
Hyper Text Transfer Protocol
 Transfer text, anchors, graphics and
sound
 Uses port 80

TCP/IP
Used for sending and receiving packets
via the internet
 Each computer must have a separate
and unique IP address
 TCP is what the router uses to attach
the IP address to packets being sent

IP addresses
Uses Four 3 digit numbers separated by
a period
 can use the numbers 0 – 255
 ex:

 172.0.0.1
 205.52.45.31
DNS Server
resolves domain names to IP addresses
 This is why you can type in google.com
in the URL and find the site for Google’s
search engine
 What’s Google’s IP address?

DHCP Server
This server will hand out an IP address
to a network computer when it is booted
up.
 The IP can be changed with RELEASE
or RENEW
 Set up by your network administrator

IPCONFIG
Let’s you see your computer’s IP
settings
 Let’s try it
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IP Classes

Class A
 Used with large businesses and small
countries
 Subnet mask : 255.0.0.0

Class B
 Used with large businesses
 Subnet mask: 255.255.0.0

Class C
 Used for small businesses and personal use
 Subnet mask: 255.255.255.0
FTP
File Transfer Protocol
 Uses Port 21
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Email Protocols
SMTP – for out going mail
 POP3 – for in coming mail

 Formats include MIME and Bin Hex and
UUEncode
Access

Having rights to connect to a server or
folders to FTP
Anchor
Used for Hyper links
 <a> </a> tags
 Can include images, text, and image
maps

Tables vs. CSS
Layout of a Web page
 Tables were the old way

 Static, didn’t display as well from one
browser to another

CSS was developed to include
positioning elements as well as
changing the look and feel of text,
graphics, etc.
 Uses the <div> </div> tags for DIViding up
the page into divisions.
Domains

Common names of websites
 Google.com
 Yahoo.com
 espn.com
 murrayschools.org
ISP

Internet Service Providers
 Qwest DSL (Direct Sub Link) – Uses
Ethernet
 Comcast Cable – Uses Coaxial cable
VPN

Virtual Private Network
 a tunnel into an network from home
Searches

Search engines
 Google
 Yahoo
 MSN

use quotations to search for specific
phases
Email encoding
Uuencoding
 Bin Hex
 MIME
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Bandwidth

The amount of data that can be sent
through a connection
Safety - Firewall

Firewall set up to block programs from
the internet from running on your
computer
Virus

– sent in email attachments.
Propagates itself when opened.
Worm
–
does not have to be run or opened
to propagate itself on a network
Trojan
– You think your running one
program, but it’s doing something
behind the scenes
 Trojan
Certificate Server
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Sends an electronic “certificate” to a
computer from the network to tell the
computer it is a legitimate program to
run
SSL
Secure Sockets Layer
 HTTPS
 Encodes the information
 Used with most online orders
