Transcript Web design and implementation Dr. Tim King 13th May 2008 My CV  Computer Lab 1973-1981 – Wrote a relational database for Ph.D.   Lecturer, University of.

Web design and implementation
Dr. Tim King
13th May 2008
My CV
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Computer Lab 1973-1981
– Wrote a relational database for Ph.D.
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Lecturer, University of Bath 1981-1983
R&D Director 1984-1986
– Wrote AmigaDOS
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Founded Perihelion with Jack Lang 1986
– Distributed OS, embedded systems, database systems
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Founded UK Online 1994
– First UK ISP with content
– Sold to EasyNet 1996
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Independent consultant
– Technical Due Diligence for VCs
– Advice for Sainsbury’s, Sony, Home Office etc
– Strategy for small companies and following M&As
2/14
Web design
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Get the domain name right
– Inventive: business.com vs PlentyOfFish (dating site)
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Design is important
– But functionality more so
– Integrate good design with backend databases
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It’s another type of publishing
– Web publishing is no different from other types of publishing
– Spelling, grammar, point size, broken links, incorrect captions
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Navigation is important
– Make the navigation clear
– Three clicks maximum to get anywhere
– Hard when Sainsbury’s have 25,000 line items
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Common mistakes
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Too much text
Frames
Huge images
Distracting colour schemes
Flashing gifs, scrolling text
Music
Unclear navigation
Unreadable
Cluttered
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Useless Title
Mystery Meat
Navigation you have to roll over
Zero intelligible content
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Refuses to work with IE
Only works with IE
Requires Flash
Assumes screen size
Assumes font size
Contains errors
www.webpagesthatsuck.com
4/14
Poor design example
Mixture of
fonts
Title seems to
be confused
with keywords
Navigation a
mess
Far too much
material
Needs more
than 1024x768
5/14
Good design example
Quick links
to sub areas
Pop-over
sub-menus
Recent news
stories
Clear link to
technical
support
Search clearly
available
Services for
subscribers
Special event
links
Discussion
forums
Consistent
navigation
6/14
Protected and encrypted pages
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Most web sites are open to all
Protected pages for
– Subscribers, Suppliers, Customers, Staff
– Protected by
• Username / pw; IP address; Domain name of browser
• Combinations of these
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Most traffic to and from web sites is in clear
– Potential eavesdropping possible
– Secure Socket Layer (SSL) encrypts data
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Widely used technology
– Used whenever privacy is important
• Payment
• Secure communication (spooks, terrorists, medical)
7/14
Dynamic pages
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HTML with extra tags pre-processed
– Java Server Pages (JSP)
– Active Server Pages (ASP)
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AJAX (Asynchronous Javascript and XML)
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Define page with named sections
Make XMLRequest call with data entered
When result returns update DOM
No need to refresh entire web page
Google Web Toolkit
• Java and AJAX
• http://code.google.com/webtoolkit
• Desire to produce web apps that compete with local
ones
8/14
Page transition diagram
Home page
Help
Search
Company
Sitemap About Us Contact
Products
Product
Services
Service 1
Support
Free
Paid
search
Service 2
Payment
Downloads
Chat
Service 3
Static pages
Service 4
Protected pages
Dynamic pages
Applications
Encrypted pages
Shortcuts
Search from every page
Payment from free support page
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Multiple targets
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Different devices
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Different browsers
Different bandwidth, resolutions, screen sizes, colours, printers
Phones & PDAs
TV: Open TV, DVB-TAM-HTML, WebTV
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XML helps, but doesn’t solve everything
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Phones and PDAs have different physical
characteristics
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WAP issues
Small screens
Battery life essential issue
Java Midlets a step forward
TV and other streaming media have different
metaphors to the Web
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Device limitations
Audio important
High colour depth, poor display quality
Evolution: Text -> Still Pictures-> Moving Pix-> 3D
10/14
Merchant Systems
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Requirements
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User logon required?
Remember credit card details?
Same price for everyone?
Special offers (free delivery if over $100 spent)
Backend integration?
Help desk support?
Online credit checking?
Order picking?
Online stock shown?
Examples
– Microsoft .NET, FatWire, InterShop
11/14
Outline Physical Design
Load balancer
Web Server
(static data)
Application Server
(business logic)
Database server
(orders)
Legacy
(stock control)
Big IP
Apache
J2EE
OPS
IBM
12/14
Sizing
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Scalability
Lastminute.com system design
– How many people?
– At the same time?
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Number of
products
Size of downloads
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Ring tones 10K
Music 4M
Software 200M
Movie 2G
Reliability
BigIP
WebServer
WebServer
BigIP
WebServer
AppServer
AppServer
Database
Database
WebServer
13/14
Site performance
(Netcraft.com)
Time since reboot varies from around a fortnight to a year
Note
scale
14/14