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Internet & Web Pages:

Internet & Web Pages

Aims & Objectives:

Aims & Objectives Brief Intro and History of the Internet Creating A Web Site Introduction to HTML Introduction to Information Architecture

History of the Internet:

History of the Internet ARPANET - the US department of defence wanted to develop a computer network that could withstand nuclear attack Unintended consequences: huge use of Email Soon became the tissue of a huge network and networks

Early Arpanet:

Early Arpanet TCP/IP (unifying protocol) Transmission Control Protocol (how data is broken up into packets and reassembled at the end) Internet Protocol (how packets reach their destination) FTP Email Telnet

The 7 Layers of the OSI Model:

The 7 Layers of the OSI Model OSI (Open System Interconnection) Model consists of 7 layers Layer 1 (Physical): hardware Layer 2 (Data Link): handling errors of layer 1, flow control, synchronisation Layer 3 (Network): switching and routing, logical paths, virtual circuits Layer 4 (Transport): end-to-end system services, ensures complete data transfer Layer 5 (Session): connections between applications Layer 6 (Presentation): independence from difference in representation (syntax layer) Layer 7 (Application): end user processes (telnet, ftp)

Hypertext:

Hypertext Vannevar Bush “As We May Think” 1945 Director of the Office of Scientific Research and Development The Memex http://www.theatlantic.com/unbound/flashbks/computer/bushf.htm Ted Nelson Literary Machines 1965 Xanadu Led to Software such as Hypercard

The World Wide Web:

The World Wide Web Created by Tim Berners Lee, a researcher for CERN, in 1989 Originally to aid researchers find information through a linked texts Used HTTP for protocol and HTML for content of pages Still no images at this point

Early Browsers:

Early Browsers 1993 only 100 web servers First Browser well known called “Mosaic” Could view images as well as text Marc Andreesen one of the early developers of Mosaic left to form Netscape

Early HTML:

Early HTML Early HTML - only text, links and images Netscape 2.0 - could use tables and embed 3rd party applications (through plug-ins) shockwave, video (mpeg), real audio In 1996 Netscape 3.0 could see JAVA and developed the scripting language javascript

Internet Explorer Catches Up:

Internet Explorer Catches Up Up till version 4.0 Internet Explorer inferior to Netscape Then makes quantum leap through use of DHTML (Dynamic HTML) Style Sheets Java performance Netscape remains the only true cross platform Browser

The Current Browsers:

The Current Browsers Once upon a time, big separation of browser/email/ftp Emacs: unified development environment Now browsers also can do it all (monolithic) Internet Explorer Browser Email (Outlook Express) HTML Editor (Front Page Express) News Reader Net Meeting Netscape Communicator Browser (Navigator) Email (Messenger) HTML Editor (Composer) News Reader Conference

Latest Developments:

Latest Developments File Sharing Napster, Gnutella, Morpheus Dot Net XML based Web Services “Semantic Net” Broadband Media Delivery over the Web

Create a Web Page:

Create a Web Page Open MS Word Create new document or open existing one Save as HTML

Page Edited:

Page Edited

The Page in HTML:

The Page in HTML <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1252"> <META NAME="Generator" CONTENT="Microsoft Word 97"> <TITLE>Steve's HTML Page</TITLE> </HEAD> <BODY> Steve's HTML Page </BODY> </HTML>

Tags:

Tags HTML is a markup language Tags are items surrounded by angle brackets containing codes indicating how text should be displayed E.G. Hello appears Hello is the start-tag and is the end tag

Editor vs Handwritten HTML:

Editor vs Handwritten HTML Using Editor is imprecise but easier Writing HTML code by hand is laborious but more powerful

More HTML:

More HTML Classic HTML works on a principle of semantic coding - markup is based on meaning (e.g this is emphasised, this is a heading, this is a subheading) rather than look (this is font size 16) However pure HTML doesn’t really exist any more

Headings:

Headings H1 to H6 used to indicate importance of topic In practice we rarely use less than H3 Using tag to emphasize severely frowned on users cannot control the display of the text speech browsers cannot register the importance of the section

Emphasis:

Emphasis The tags and are identical in as much as they produce italics, but the is more classical and better style (semantics!) The tags and are identical in as much as they produce bold text but again the is more classical

Lists:

Lists Two types: <OL> ordered list, which numbers the items of the list <UL> unordered list, which separates items with bullet points List items are enclosed with the tags <li> and </li>

Paragraphs:

Paragraphs Used with the tags Also the tag is used to create simple line breaks within the same paragraph

Hyperlinks:

Hyperlinks What makes the web the web - a document can link to another document Links can be either absolute or relative Absolute specifies a full URL e.g. http://www.microsoft.com Relative specifies a file relative to the current file e.g index2.htm

Structure of a Hyperlink:

Structure of a Hyperlink Hyperlink uses the following syntax <A HREF=”index2.htm”>My second page</A> Where HREF = hypertext reference i.e. The file to link to “My second page” is the text being clicked

Tags with Attributes:

Tags with Attributes The <A> (anchor) tag is interesting in that it has an attribute (HREF) which has to be specified The tag is similar as is The <IMG> tag The <BODY> tag

Font Tag:

Font Tag Remember that the use of the FONT tag is frowned upon and so should be used sparingly

IMG Tag:

IMG Tag <IMG SRC=“next.gif” WIDTH=200 HEIGHT=360 BORDER=0 ALT=“Go to Next Page”> width and height specify the size the image will take up within the page (not constrained by the original size of the image) border is not normally used except when the image is to be a hyperlink itself ALT a very important tag meaning alternative text I.E when the browser cannot display the image

Images for Hyperlinking:

Images for Hyperlinking Used all the time in navigation bars You must specify the border to be 0 otherwise an unpleasant blue border will appear around the image

The Body Tag:

The Body Tag Very important tag which determines the background of the page <BODY BGCOLOR=“#ff00ff” BACKGROUND=“waves.gif”> If a colour is specified, that becomes the background colour, but if a background image is also specified this will override the colour

The META Tag:

The META Tag Technically relevant tag controlling the behaviour of browsers and robots Two possible attributes <META HTTP-EQUIV="name" CONTENT="content"> controls browser display (equivalent to http header) <META NAME="name" CONTENT="content"> controls other aspects; not clearly separated

Distribution:

Distribution Each HTML file exists only as a node within a vast network Each image that appears on it comes from a separate file which is not part of it

Back To Word:

Back To Word Adding a picture using Insert>Object>Microsoft Word Picture

Look at the HTML now:

Look at the HTML now Steve's HTML Page <IMG SRC="Image16.gif" WIDTH=288 HEIGHT=192> </BODY> Image now automatically generated by Word

Adding a second HTML file:

Adding a second HTML file Create a new file in word Save that has HTML in the same directory as the first file Make a link to it from the first file (write some text, select it, click on the globe+link icon, then select the file you’ve just created as being the linked file)

What is a web site?:

What is a web site? A lot of linked documents, a heterogeneous information space A machine of meaning for a variety of users It therefore requires thought regarding Intended Audience Design Motifs Information Architecture

How To Structure a Web Site:

How To Structure a Web Site Hierarchical tree structure, categories, sub categories Data Driven database with pages dynamically created Hypertextual pages with random, content driven links to other pages

Hierarchical:

Hierarchical

Hierarchical:

Hierarchical The most common form of web site because mental model can be easily created by human beings Problematical because of items which cross categories (tomato in fruit/vegetable schemas) Design challenges (narrow and deep or broad and shallow) Maintenance might not be easy

Data Driven (see FEIS site):

Data Driven (see FEIS site) Usually for subsections of web sites e.g staff directories, telephone numbers, knowledge bases Advantage is separation of content and form visual appearance of site can be redesigned at will Often rigid and bland

Hypertextual:

Hypertextual Links pages in web sites Or whole sites (academic) Good for serendipitous searching (we want to find something but we’re not sure what it is) Can be disorienting (we don’t know where we or or how to get back to where we came from)

Hybrid Sites:

Hybrid Sites

What Next:

What Next Read Parker Module Networks (Chapter 8 and 9) pp 295-388 Read Unit 6 on the Web Site