Transcript introduction to web design

LIS650
web site architecture & design
lecture 0
Thomas Krichel
2003-11-01
structure of talk
•
•
•
•
introduction to the course
talk about you
the basic ingredients of the web, without html
introduction to our basic technical set up
• Krug on usability
• images
• introduction to html
Course history
• Course was first run as an institute 2002-05-13
to 2002-05-17
• Title was "Webmastering I: the static web site".
• To the curriculum committee, this title did not
sound academic enough.
• But webmastering is really what we want to learn
here.
webmaster
• There are two available definitions that come to
mind
– A webmaster is a person who has write access to a
set of files that are available for display on the World
Wide Web.
– A webmaster is a person who has control over a
software installation that can deliver web pages.
• The second is more stricter. We mostly use the
first one.
webmastering
• Webmastering combines many aspects:
–
–
–
–
–
Authoring pages
Work on the organization of data to fit onto pages
Set display style of different pages
Organize the contribution of data
Maintain a technical web installation
• Some of them can be learned in a course, but
others can not.
• Emphasis has to be on learnable elements.
teaching philosophy
• Point and click on a computer software is not
enough.
• Explain underlying principles.
• Promote standards.
– HTML 4.01
– CSS level 2
• Avoid proprietary software.
webmastering I
• Deals with the maintenance of a static web site.
Such a web site remains the same whatever the
user does with it.
• Topics include
– html
– css
– site usability and information architecture, as far as
relevant for static web sites
– http, uri, web server
things this course does not do
• Forms: allow you to design forms that users fill
in. But you do not have the programming skills to
do something with the form. That is part of
webmastering II, if ever held again.
• Frames: allow you to put several documents into
one physical document. Most experts advise
against them.
• Any html elements that require executable
contents are not covered.
• We do not cover image maps.
Other courses: webmastering II
• Deals with building dynamic web sites.
– Users fill in a form
– Users submit the form
– Web server return a page that is specific to the
request of the user.
• Teaches a language called PHP, that is widely
used to generate such web sites.
– Gets you introduced to computer programming
– Gets you to train analytical thinking.
other courses: webmastering III
• Deals with XML
– XML is a syntax to encode any kind of data.
– XML can be constrained to only allow certain types of
data (XML Schema)
– XML can be transformed to render the data in various
ways (XSLT)
• Achieve a separation of contents and
presentation of a web page.
• advanced course, has both Schema and
Transformation
The world wide web
The World Wide Web (Web) is a network of
information resources. The Web relies on three
mechanisms to make these resources readily
available to the widest possible audience:
– A uniform naming scheme for locating resources on
the Web (I.e. URIs).
– Protocols, for access to named resources over the
Web (e.g., HTTP).
– Hypertext, for easy navigation among resources (e.g.,
HTML).
URI introduction
• Every resource available on the Web -- HTML
document, image, video clip, program, etc. -has an address that may be encoded by a
Universal Resource Identifier, or "URI".
• URIs typically consist of three pieces:
– The naming scheme of the mechanism used to
access the resource.
– The name of the machine hosting the resource.
– The name of the resource itself, given as a path.
example URI
• http://openlib.org/home/krichel
This URI may be read as follows: There is a
document available via the HTTP protocol,
residing on the site openlib.org, accessible via
the path "/home/krichel".
• mailto:[email protected]
This URI may be read as follows: There is email
user krichel in a domain openlib.org to whom
email may be sent.
client / server protocol
• The web operates mostly on http.
• This is a client-server protocol.
• The client software is run on the local PC that
you are using.
– It is called a web browser or user agent.
• Our server is a piece of hardware called
wotan.liu.edu or wotan for short.
– It runs the Debian GNU/Linux operating system on a
Intel architecture.
– It provides http daemon software that serves http
requests. The particular software is called Apache.
communication with the server
• The protocol for communicating with the server
is the secure shell, short ssh. It is based publickey cryptography.
• We two two ssh clients
– For file editing and manipulation, we use putty.
– For file transfer, we use winscp.
– Both are available on the web.
• Telnet and ftp servers are not available on
wotan. Telnet and ftp do not encrypt the
communication stream; therefore they are not
secure.
registration time
• As part of the course, you are being provided
with web space on the server wotan.liu.edu, at
the URL
http://wotan.liu.edu/~username
where username is a user name that you will
chose now.
• It is my intention to maintain this web space for
you into the foreseeable future.
• You should also choose a password, now.
• I will now register you.
login time
• Use putty, port 22 to wotan.liu.edu
• set other attributes of the session as you like,
using the menu on the left, for example
– colors
– font shapes and sizes
– bell
• Save the session as “wotan” (in the first screen)
to save all the customization.
• Do the same thing at home!
free software
• I maintain wotan.liu.edu server
• You can build your own server if
– you have Internet access
– you have an old PC
• All the server software, as well as putty and
winscp are free, open-source.
• It is one of my fundamental beliefs that free
information should run on free software.
• The library community can learn a hell of a lot
from the free software community.
• See my talk of 2003-11-07.
installing putty and winscp at home
• Go to your favorite search engine to search for
putty.
• Download and run windows-style installer
software to install putty.
• Do the same thing with winscp.
• Download and install a recent version of at least
two browsers, for example Netscape Navigator
and Microsoft Internet Explorer.
putty and winscp
• You can either maintain files on wotan
– by logging into wotan
– using a file editor there, for example nano
– past experience has shown that this is hard for
students with no UNIX experience.
• You can also maintain text files locally
– each time you make a change, you save the file and
upload to wotan using winscp.
– you can use notepad locally to maintain text files
– you may be able to use Microsoft Word to maintain
text files, but safe them as text, not "web page".
create a web page in MS notepad
• Open Microsoft notepad. Type the text
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML
4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html><head><title></title></head>
<body><div></div></body></html>
• save as empty.html
• If you want to open it again in notepad, open
notepad, then select file/open, list all files and
open empty.html. Don't click on the file and
don't choose edit in the context menu.
creating web pages in MS Word
• My best advice: don't do it.
• Microsoft word enters special code into the web
page that will make validation of your pages fail.
• If you work with Microsoft windows, use save as
plain text, with the encoding UTF-8.
• But don't work with it!
• It will all end in tears!
upload and view file
• Once you have your file empty.html, use the
menus of winscp to upload it to your file in the
public_html directory of your home directory on
wotan.
• Once it is there, use a web browser to view it at
http://wotan.liu.edu/~user/empty.html, where
user is your user id.
• Then validate it at http://validator.w3.org.
– enter the url of the page that you want to validate
– hit the validate button
public_html
• Is your web directory. It is automagically created
for you when Thomas registers you.
• The web server will map requests to
http://wotan.liu.edu/~user/file to show the file
public_html/file.
• Here user stands for your user id, and file is the
file name.
• If file ends with ".html" or ".htm" the web browser
will be told that the file is a html file. It will be
rendered accordingly by the browser.
index.html
• The web server on wotan will map requests to
http://wotan.liu.edu/~user to show the file
~user/public_html/index.html
• If this file is not there, the server will prepare a
html document from the list of files that it finds in
the directory and send it to the user agent.
• Once you have a file index.html, the web user
can no longer see the individual files in your
directory.
Web site usability
• This is a big topic in the LIS community.
• But it really comes down to common sense.
• There is no absolute right/wrong, but one can
learn from experts
– Krug
• less technical
– Nielson
• also has tons of technical advice
– Morville and Rosenfeld
• library focus, less useful
Krug's book
• Short
• Deals mainly with the issue of how to build
commercial web sites.
• Here user confusion is the cause of lost money.
• He mainly deals with sites that have
– extensive scale
– searching and browsing
– user interaction
• Our sites for this course do not have these
features.
Krug's advice
• Krug's rule #1: Don’t make me think.
– a site should be obvious
– if it can not be obvious, it must be self-explanatory
• Things that make think
– non-standard terms
• jobs
• employment opportunities
• job-o-rama
– links and buttons that are not obvious to find
search example
• Contrast
– http://www.sl.nsw.gov.au/webcat/srchhelp_w.cfm
– http://www.amazon.com
for search.
• Note, however, that search forms are not part of
this course.
How people use the web
• Received wisdom would suggest
– people read the page
– then make the best decision.
• That is wrong. Instead, people
– scan pages
– look for something that seems vaguely related to the
current aim
– click on it if clickable
• User satisfice (term by Herbert Simon, a cross
between satisfying and sufficing)
why do they do that?
• Why do users satisfice?
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Users are in a hurry.
The penalty for a wrong guess is low.
Weighing option does not seem much help.
Guessing is more fun.
• Users don't figure out how things work. They
muddle through
– It does not matter how things work
– When they have found something that is useful to
them, users stick with it.
Krug's advice
• Create clear visual hierarchy.
– the more important something is, the more prominent
it should be
– things that relate logically should relate visually
– things that are part of something else should be
nested visually within it.
• Use conventions
– they have proven useful
• Break pages into separate parts
• Make obvious what is clickable
• Reduce visual noise.
Krug's advice
• Krug's second law: it does not matter how many
times I have to click as long as each click is a
mindless, unambiguous choice.
• Krug's third law: Get rid of half the words on
each page, and then get rid of half of what is left.
– no happy talk
– no instructions
Building navigation
• For commercial web sites, people are usually
trying to find something.
• It is more difficult than in a shop
– no sense of scale
– no sense of direction
– no sense of location
• Navigation can
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give users something to hold on to
tell users what is here
explain users how to use the site
give confidence in the site builder
Navigation elements
• Site ID
• Sections of items
• utilities
– link to home page
– link to search page
– separate instructions sheet
• Current location needs to be highlighted.
navigational elements on the page
• All pages except should have navigation except
perhaps
– home page
– search page
– instructions pages
• Page names are also important
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–
–
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every page needs one
in the frame of contents that is unique to the page
the name needs to be prominent
the name needs to match what users click to get
there.
ways to do navigation
• Breadcrumbs like "store > fruit & veg > tomato"
• Tabs, like the ones seen in Amazon.com
– Krug's favorite.
• A table on the left or right hand side that stays
the same
– will do just fine for us
• Pulldown menus
• Rollovers
Home page design
• For large site, it is a mission impossible
• But above all it has to convey the big picture
– tagline
•
•
•
•
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clear and informative
just long enough
differentiating
clear benefit showing
lively, personable and sometimes clever
– welcome blurb
– but no mission statement
bad home pages
•
•
•
•
put a banner add even though they don't need it
let deals drive the home page
promote everything
are greedy for user data
That's about all from Krug, folks
• The rest of the book is about how to do usability
testing.
• Before he gets to that, we have the best part of
the book, the cartoon page 131-132.
• I will distribute and discuss this now.
• And then we start about images
special topic: images
• The appeal of the web to the masses has a lot to
do with its capability to transport image.
• Image format are independent of the web, but
there are two classic format that are widely
supported by user agents.
– GIF
– JPEG
GIF
• stands for graphics interchange format.
• developed by CompuServe.
• unresolved copyright issues make the format
abhorred by the free software community.
• 250 colors maximum
• uses a loss-less compression technique
GIF has three tricks
• interlacing:
– when downloading the file, the browser can show
every forth row first
– user gets in an idea of the picture before it is sharp
• transparency
– some GIFs are transparent, so you can see them on
top of already exist
– technically, the GIF has one color as the background
color, and pixels of that color are ignored by the user
agent
• animation
– some GIFs are in fact sequences of GIFs that can be
rendered one after the other.
JPEG
• The Joint Photographic Experts Group is a
standard-making body for images
• They can support thousands of colors.
• The compression is lossy, i.e. the JPEG file will
look like the original image, but not be the same.
• The compression does not work well with
drawings.
• There are no copyright and patent problems with
JPEG
HTML and XHTML
• HTML is the hypertext markup language
• HTML is a markup language that is widely used
on the Word Wide Web (WWW)
• The latest, and probably last version of HTML is
at http://www.w3.org/TR/html4/
• The WC3, the standard making body for the
WWW, have issued XHTML, a replacement of
HTML that is compatible with XML.
• We will ignore XHTML for the rest of the course.
what is markup?
• Everything in a document that is not content.
It can be give in two ways
• 1: Procedural
– Codes identify point size, style, font, etc.
– Usually understood by defining tool
– Example: M$ Word
• 2: Descriptive
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–
–
–
Describes purpose of text within the document
Chapter head, Paragraph, Section Head, TOC
Structure and Style are kept separate
Example: LaTeX, SGML
Procedural vs Descriptive
SGML
• Standard Generalized Markup Language
• Descriptive approach with three separate layers
– structure: types of information in document
– content: the information itself
– style: matches typesetting with structure
• Developed for the publishing industry by a group
around Goldfarb.
• So complicated that no software implements it fully
• Document Type Definition (DTD)
– Defines the structure
Document Type Definition (DTD)
• Describes information the document handles
– e.g Title,TOC, Chapter, Section
• Relationships between fields
– e.g. A Chapter contains Sections
• Consistency
• Logical structure
• Information defined by tags
HTML
• HyperText Markup Language
• Defines an SGML DTD
–
–
–
–
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Head, Title, Body, Paragraph, etc.
Headings, Bold, Italic, etc.
Table, List, Image, etc.
Links to other documents
Forms
• Style applied by Web Browser
– User has some control
HTML tags
• HTML markup is written as tags. Tags are written
as pairs (typically)
– begin with <atag>
– end with </atag>
– atag is the tag name
"tag start"
"tag end"
• Can be nested
• Can contain non-markup data
• Tag names are case-insensitive, but it is best to
use the same case, consistently, for human
readability.
attributes to tags
• <atag attribute_name_one=“value_one”
attribute_name_two=“value_two”>
• Here attribute_name_one and
attribute_name_two are attribute names
• and value_one and value_two are attribute
values.
common frame for pages
• Put the following in your pages:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD
HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html><head><title></title></head>
<body><div></div></body>
</html>
• The first three lines are the SGML document
type declaration that says which kind of HTML it
is.
Homework
• Look at course home page
http://wotan.liu.edu/home/krichel/lis650w03a
• Send [email protected] your secret word for
course result delivery.
• Prepare a one-page max summary of the type of
website that you want to build, bring printed copy
with you next week.
• Prepare for quiz at the beginning of next lecture.
http://openlib.org/home/krichel
Thank you for your attention!