Quick poll

... is the inter-connexion of local computer network into a global network, using standard low-level protocols (TCP/IP).

© portices.fr http://www.portices.fr/formation/Res/Internet/Res/InternetMonde.gif

• e-mail
• peer-to-peer (P2P) file sharing
• online chat
• ...
• the world wide web

A global decentralized information space, based on hypertext navigation.

Note

Many internet applications now use the WWW as a front-end, bluring the difference between Internet and the web.

A partial and subjective one...

http://commons.wikimedia.org/wiki/File:Vannevar_Bush_portrait.jpg

Memex, As We May Think (1945)

What is this?

Can you guess?

http://commons.wikimedia.org/wiki/File:Douglas_Engelbart_in_2008.jpg

Computer mouse, GUI

http://en.wikipedia.org/wiki/File:Ted_Nelson_cropped.jpg

Projet Xanadu, “Hypertext”

http://www.flickr.com/photos/mayhem/3353514936

The World Wide Web, W3C

http://www.w3.org/

“Lead the web to its full potential”

• consortium of companies, universities...
  • including Université de Lyon
• standardizing open and royalty-free technologies

http://commons.wikimedia.org/wiki/File:Steve_Jobs_Headshot_2010-CROP.jpg

Modern smartphones, mobile web

http://blog.kissmetrics.com/evolution-of-web-design/

http://evolutionofweb.appspot.com/

http://www.wix.com/blog/2012/07/the-authentic-infographic-history-of-html5/

• HTTP
• URLs
• HTML

• HyperText Transfer Protocol (RFC 2616)
• Describes how data is exchanged between computers
• Will be studied in more detail next year...
  • ... but you need to know a minimum.

• Resource: any piece of information available on the Web (document, image, video...)
• Server: a computer “containing” resources, always connected to the internet
• Client: a computer/smartphone/tablet... used to display resources

http://commons.wikimedia.org/wiki/File:Client-server-model.svg

• Uniform Resource Locator (STD 66)
• Structure:

http://champin.net/enseignement/web/

• protocol
• server name
• resource local name

• Anyone can link to anything

NB: URLs are sometimes called URIs or IRIs → same thing

• HyperText Markup Language (HTML5)
• Describes how data is interpreted by the client in order to display a hypertext

Note

HTML is the main language of the Web but not the only one: CSS, Javascript, XML... We will only address HTML and CSS this year.

Nowadays, very few people write HTML by hand: people use WYSIWYG tools and generators. So why should you learn how to write it?

• HTML generators can not do everything
• generated HTML usually requires manual fine-tuning
• as computer scientists, you may have to write those generators
• you may have also to write programs that consume HTML (for processing or display)

WYSIWYG is not ideal for HTML:

• HTML is not (or should not be used as) a presentation language (anymore)
  • HTML describes the structure of the page
  • CSS will be used to describe the presentation
• Keeping presentation separate allows web pages to display on multiple devices
  • big computer screen, laptop, smartphones, screen-reader...