ENGS 112 Lecture 2 HTML Primer See text or web for more information and examples.

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ENGS 112 Lecture 2 HTML Primer See text or web for more information and examples.

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ENGS 112 Lecture 2 HTML Primer See text or web for more information and examples. HTML is HyperTex Markup Language HTML is a “specialization” of SGML HTML is a language for describing how web pages should look. HTML has some constructions for - PowerPoint PPT Presentation

Transcript of ENGS 112 Lecture 2 HTML Primer See text or web for more information and examples.

Page 1: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

ENGS 112Lecture 2

HTML Primer

See text or web for more information and examples.

Page 2: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

HTML is HyperTex Markup Language

HTML is a “specialization” of SGML

HTML is a language for describing how web pagesshould look. HTML has some constructions forforms, frames, etc that make it a bit more dynamic.

HTML is very simple....we’re going to go overonly the basics...other sources:

- Dietel- read the source of other pages- web HTML manuals and how-tos

Page 3: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Basic syntax of an HTML construct

• HTML uses “tags”• tags typically have a beginning and a closing version.• example....every html page should start with the tag

<html>

and end with

</html>

Not essential but good style.

Page 4: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Basic structure of an HTML page<html><head><title>Our first page!!</title></head><body>Blah, blah, blah</body></html>

Page 5: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Some tags

Headings <h1>...</h1>, <h2>.....</h2>,....

New paragraph <p>

Line Break <br>

Horizontal rule <hrule>

Let’s try them now....

Page 6: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Links and URL’sWeb link construction

<a href=“http://www.cnn.com”>CNN’s web site</a>

<a> </a> HTML anchor tag

http:// is the protocol or scheme

www.cnn.com is the server name

anything following that is the path name

“CNN’s web site” is the anchor

Page 7: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Absolute and relative links

<a href=“http://www.dartmouth.edu/~gvc/”>Dartmouth</a>

is an absolute reference to a web page.

<a href=“somefile.html”> Another link</a>

is a relative link.

Page 8: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Text properties<b> </b> boldface

<i> </i> italics

<blink> </blink> blinking

<u> </u> underlining

<strike> </strike> striked out

Page 9: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Backgrounds

<body bgcolor=“#rrggbb”>

OR

<body background=“some url or relative file name”>

Where can you get some fun backgrounds?

Let’s do some searches!!!!

Page 10: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Adding images

Image formats most browsers can view

jpeg, jpg Joint Picture Experts Group

tif

gif

.....etc

<img src=“some URL or filename” alt=“picture”>

Page 11: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Images as anchors for links

<a href=“URL”><img src=“ULR”></a>

Let’s do an example......

Page 12: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

URL’s and Internet Names, addresses, etc

www.dartmouth.edu is the name of a server

The name is for human consumption...the internetuses a four number address to identify all “hosts”on the internet.

129.170.16.79

Each number is between 0 and 255.

Page 13: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Let’s buy an internet domain name!!!

Visit www.nsi.com to see what names aretaken, who owns a particular name, or buy a namefor yourself!!!

Page 14: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Domain names are hot commodities....ebay auction

Name brands and common words are all taken.

All two and three letter combinations are gone.

This is the “real estate” of cyberspace!!!

Page 15: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Networked Services

ApplicationsWWWStreaming data – audio and videoInternet telephony and videoconferencesNetworked gamesClient/serverSensor networksBroadcast TV – video on demand

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Quality of Service (QoS)

Constant bit rate (CBR)Variable bit rate (VBR)End-to-end delays, latencyBit error ratesAdmission policy and blocking probabilities

Page 17: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Engineering Challenges of Different Content Types

Content Bandwidth Bursty QoS?

Web, data Medium Yes No

Voice Low Yes Yes

TV, video High No Yes

Monitoring Variable No No

Page 18: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Network Elements

Links and switches – abstractions as graphs and queues

Service characterizations –

total delay = trans + prop + qd + proc

Page 19: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Network Mechanisms

Multiplexing – sharing a common channel/resource

Time-division multiple access TDMAStatistical multiplexing Spatial multiplexingFrequency-division multiple accessCode-division multiple access

Page 20: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Network Mechanisms

Switching

circuit switchingpacket switchingdatagram network vs virtual circuit

switch design – Clos and other switch designs

Page 21: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Packet SwitchingSend “packets” into the network, routing each packet individually, like the post office. Packets are “routed”through the network, sorted at “switches”.Requires no setup time but no guarantee of service!!

Good for telephones, bad for web browsing!!!!

Page 22: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Network Mechanisms

Error control - detection vs correction

parity bitscyclic redundancy codes

replication for error correctionBCH and Reed-Solomon codes

error detection and correction protocolsretransmission protocols

Page 23: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Network Mechanisms

Flow control

Congestion controlproblems with long haul, high speed networksrate control (open loop)

Resource allocation

Page 24: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

Why is “convergence” achallenge?

Convergence of entertainment, telecommunications andcomputing industries.

Telecom is set up for voice.

Entertainment requiries audio and video QoS.

Computer communication is based on packet switching.

Page 25: ENGS 112 Lecture 2 HTML Primer See text or web for more  information and examples.

OEE (Due Friday, April 14)

Walrand page 93+

1.3.4.12.16.20.25.