Transcript MS Powerpoint 97/2000 format

Top Ten Tips For
Building Web Sites
In The 21st Century
Brian Kelly
UK Web Focus
UKOLN
University of Bath
UKOLN is supported by:
Email
[email protected]
URL
http://www.ukoln.ac.uk/
Who Am I?
About me:
• First started using the Web in January 1993
• Attended first WWW conference in CERN
in May 1994
• Now employed as UK Web Focus – an
adviser on Web technologies to the UK
Higher and Further Education communities
• Based at UKOLN, University of Bath
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1 - HTML Is Dead!
The Web:
• Great success since the mid-1990s
• Exponential growth due to the ease of creating
Web sites
<TITLE>My first Web page</TITLE>
<P>Hello world.
<P>This is easy!
But we’ve now discovered that:
• Maintenance is a bigger issue than creation
• There are other devices besides the PC
• We want automated tools to process and
repurpose Web resources
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1. HTML Is Dead! (cont.)
If we use HTML:
• We don’t have much structure in our resources
(we have <h1> but not <author> or
<borrower-number>)
• It’s difficult to repurpose information for other
platforms (PDAs, e-books, digital TV, …)
• It’s difficult to make use of machine-to-machine
processes with HTML
Issues:
• Should we be buying HTML authoring tools?
• Should we be providing training in HTML?
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2. XML Is The Future
XML:
• Extensible Markup Language
• Designed to be lightweight and suitable for the
Web
• Is the future
• Actually XML is the present! The XML
foundations are mature and widely used
<title>How The Web Was Born</title>
<author>Robert Cailliau</author>
<ISBN>3332</ISBN >
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2. XML Is The Future (cont)
Associated with XML we have (or will have):
XML Schemas
Defining structure of XML docs
(<PRICE> cannot be negative)
XSLT
Language for transforming XML docs
XLink and XPointer Better hyperlinking: link to the second
paragraph after the 3rd image
XML Signature
Digital signatures for XML resources
XML Query
Mechanism for querying XML
resources
2. XML Is The Future (cont)
Conclusions:
We need XML in order to:
 Address management and development
problems we’re encountering today
 Develop richer, more robust services for
tomorrow
Issues:
• How to we kill off HTML?
• How do we make a start with XML?
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3. XHTML - A Migration Strategy
How do you get to a bright XML future from an
existing setup based on legacy HTML?
XHTML:
• Is HTML represented in XML
• Looks very similar to HTML except:
<p>tags must be lowercase ..
<hr /> - empty elements must be closed
<img src=“foo.gig width=“20 .. /> attributes in quotes
Using XHTML means:
• You will get the benefits of XML without a major
change in working practices
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HTML browsers have to check every tag. XML browsers build a tree
structure, which will be more efficient. A strict XHTML Web site should
be processed more quickly by XML browsers!
http://www.xhtmlguru.com/links.htm
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3. XHTML (cont)
XHTML:
• Is the latest version of HTML (there will be no
HTML 5.0)
• Has been developed by W3C to be accessible,
interoperable, modular, etc.
What’s the catch?
• Not many XHTML authoring tools available yet
• Migration from HTML to XHTML
• Tools such as HTML-tidy may help - see
<http://www.w3.org/People/Raggett/tidy/>
• See <http://www.xhtml.org/>
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4. A Useful XML Application: RSS
XML isn’t just some vague format which may be
relevant sometime in the future.
There are a number of lightweight XML applications
which you can (and possibly should) use today:
RSS
• RDF Site Summary
• A lightweight format for news syndication
• An XML solution you can deploy today - without
needed to buy new software or (scarce) technical
expertise
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4. A Useful XML App.: RSS
Why would I want RSS?
• You provide news in your organisation and you
want to make it available:
 On your Web site
 On other Web servers in your organisation
 On third party Web sites (e.g. you are a
national or regional service and want to
provide information to your community)
• You want to do this in an automated way - so you
don’t have “Merry Christmas” news items at
Easter
• You have limited budget and technical expertise at
your disposal
4. RSS Example – W3C News
The W3C Web site provides news on its home page. It wants to
disseminate this news widely. Rather than just hoping that people
will follow links to its home page, W3C makes the news information
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4. Creating RSS
RSS is a very simple format
<title>Royalty-Free Patent Policy</title>
<link>http://www.w3.org/News/2002
#item32</link>
<description>26 February 2002:
Responding to comments …</description>
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RSSxpress is one example of a
(Web-based) tool for creating (and
viewing) RSS news feeds.
Other approaches to creation:
• From a backend database
• XSLT transformation from
XHTML
• HTML-“scraping”
4. Viewing RSS
There are a range of tools
for viewing RSS files:
• RSSxpress: a CGI
script developed at
UKOLN
• RSSxpress Lite: a
Javascript solution
also from UKOLN
• Feedreeder: a
desktop application
5. Accessibility Is Important
Accessibility is important and not just for obvious
reasons:
• Digital resources can be made accessible to people
with disabilities in ways that is difficult with physical
resources
• Digital resources should be made accessible for
ethical and legal reasons
An accessible Web site:
• Should be more reusable (e.g. by robot software).
• Should be based on universal redesign principles
• Should be more easily deployed on new platforms
(e.g. PDAs, e-book readers, etc.)
• Should be based on an open, neutral format - XML
6. Have a URL Naming Policy
Policies on URLs are needed in order:
• to minimise 404 messages when you reorganise
• to allow flexibility - e.g. changing the Web server's
operating system, CMS technology, etc.
• to make your Web site more easily mirrored and
preserved
http://www.foo.ac.uk/services/library/resources/
policies/getdoc.asp?name=URL_naming
This example is:
•
•
•
•
Long(ish)
Has mixed case and uses an underscore
Reflects a backend technology (Active Server Pages)
May not be indexed
7. You Will Need A Browser Policy
The Web:
• Originally designed to overcome application
dependencies, versioning issues, etc.
Unfortunately:
• Buggy browser software was released and
deployed widely
• There were errors and inconsistencies in the
standards and no systematic QA processes
This means:
• It is expensive to provide different versions of
resources to:
 Provide multiple versions of Web sites for different
browsers
 Test every new feature in every browsers / platform
combination
7. You Will Need A Browser Policy
What can you do:
• Do nothing – stick with “old” HTML
• Use all the new features
• Use “safe” new features, which degrade gracefully
• User-agent negotiation to deliver “safe” HTML/CSS
Since backwards compatibility failed to arrive you will
probably need to develop a support browser policy:
• “Target” browsers –which will get the full effect
• Functionality provided in legacy browsers (is it
usable, but not elegant, or completely unusable)
Your policy may also have to describe usability for:
• Browsers lacking required plugins
• Browsers with features switched off (e.g. no
JavaScript, for security reasons)
8. Think Hard About Standards
There are advantages to the use of open standards:
• Device and platform independence
• Standards should have benefited from an open architectural
review process
But proprietary formats will be very tempting:
• They can provide functionality not yet available in open
standards
• They may provide the features which users request (note
standards-compliance is unlikely to be driven by user needs)
For you to reflect on:
• Who will pay for the migration of a service from a proprietary
format to an open standards?
• Be warned: large software companies, etc. will muddy the
water with terms such as open and user-driven standards
9. You'll Probably Need A CMS
How can you:
• Deploy XML
• Manage delivery of services to a complex
environment (browser versions, platforms, etc.
• Deploy new services (e.g. personalisation)
You will probably need a Content Management
System (CMS) to develop and manage a
professional Web site
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10. Have The Open Source Debate
You'll need to address issues such as:
• Open source vs. licensed software
• In-house development vs. outsourcing
• Local vs externally-hosted software.
Note that this can be a very emotive issue for many
IT staff! However you need to have the debate.
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