1 The Latest Web Developments Brian Kelly, UK Web Focus UKOLN University of Bath Bath, BA2 7AY UKOLN is funded by the British Library Research and Innovation Centre, the Joint Information Systems Committee of the Higher Education Funding Councils, as well as by project funding from the JISC’s Electronic Libraries Programme and the European Union. UKOLN also receives support from the University of Bath where it is based.

2 Contents Data Formats HML 4.0CSS 2.0 Dynamic HTMLXML Transport HTTP/1.0HTTP/1.1HTTP/NG Addressing URLsURNsDOIs Metadata PICSDublin CoreRDF Implications

3 Web Protocols The web was originally based on 3 protocols: Data Format (user interface): HTML Transport: HTTP Addressing: URLs Data format Transport Addressing

4 HTML HTML: Defines structure SGML application Platform and application independent Simple and therefore easy to create but: Netscape / Microsoft browser wars began HTML extensions appeared (Proprietary) scripting languages add new functionality and also complexity Universal access begins to be lost

5 HTML Develops During 1997 recognition of dangers of HTML wars Netscape and Microsoft began working with W3C on development of new protocols HTML 4.0 W3C recommendation Primarily defines structure Layout tags for backwards compatibility CSS 2.0 W3C draft Used to define appearance

6 CSS 1 CSS level 1: W3C recommendation in December 1996 Partly supported in IE 3.0 Early designs attempts confirmed power of CSS but highlighted backwards compatibility issues

7 CSS 2 CSS level 2: Provides richer functionality Addressed backwards compatibility issues wprmultb.htm

8 Making HTML Dynamic DOM: Document Object Model W3C activity Enables client-side scripting languages to manipulate HTML and CSS elements and their content Sometimes referred to as dynamic HTML But: Netscape's implementation is non- standard

9 DHTML Example - 1 Making documents "collapsible" is very easy: on mouseclick in heading set visibility and display of body off

10 DHTML Example - 2 Dynamic HTML can be used to develop improved user interfaces. In this example an expanded menu is provided.

11 DHTML Example - 3 DHTML can be used to provide interactive systems - e.g. for CBL, simulation In this example the pieces can be moved.

12 Compatibility Issues Compatibility with old browsers / other browsers can be provided by: Using safe, backwards compatible features Checking for browser type by client-side scripting language Checking for browser type by server Alternatively ignore backwards compatibility

13 The End for HTML? HTML 4.0 and CSS 2.0 provide a rich environment for describing document structure and appearance But: Standardisation of new elements is slow Supporting communities with specific needs (e.g. Maths) will result in large, complex HTML Applications have specific needs (e.g. HTML 5, 6, … does not appear to resolve these issues

14 XML XML: Extensible Markup Language Can be regarded as a lightweight SGML Supported by SGML community Some support in Internet Explorer 4.0 Netscape promising support in future XML 1.0 became a W3C recommendation in Feb 1998 See

15 XML Applications MML / CML Scientific communities have defined Math and Chemical Markup Languages CDF Channel Definition Format provides a proposed standard for push technologies RDF Resource Description Framework provides a proposed standard for a metadata architecture...

16 CDF Example NewsAgent: an eLib project evaluating potential for CDF for pushing information Software to create CDF becoming available - e.g. FrontPage 98 Events Typical CDF File

17 Transport HTTP 1.0 Widely used  Inefficient  Cache unfriendly HTTP/1.1 Addresses deficiencies in HTTP/1.0 Cache-aware Available now (e.g. latest version of Apache)  Browser support?

18 Transport HTTP/1.1 Evolutionary development HTTP/NG The Next Generation Based on distributed object-oriented model Issues: Browser support Server support Note: About 40% of UK University central websites servers support HTTP/1.1

19 Addressing URLs: Provide addressing for the web Consider applications/ Problems: –Company reorganises website –Individual leaves –Company is taken over!

20 Solutions (1) URNs: Uniform Resource Names: make identification of Internet documents possible. URN identifiers are persistent and unique. See PURLs: Persistent URLs: Point to a resolution services rather than the resource itself. See

21 Solutions (2) DOIs: Document Object Identifiers Costs $1,000 to register S hdl://cnri.dlib/august95-contents DOIs use CNRI's Handles

22 Addressing: Conclusions Conclusions: No clear technological winner Performance issues Is it just for "publishers" Business model uncertain Deployment and "real world citation" issues Still need for information providers to give careful thought to URL naming schemes

23 Metadata Metadata: The missing architectural component of the Web Many developments in progress: –PICS: "this resource contains bad language rated as X" –Dublin Core: the author's name is xxx and his address is yyy –Web Collections: these set of resources are related and should be download together / printed as a single document / … –Distributed Authoring: the following can update this document –...

24 RDF Resource Description Framework (RDF): Too many ways of handling metadata... RDF provides generic infrastructure for metadata Based on XML See <RDF:Description RDF:HREF=" RDF:BAGID="Statement_001"> John Smith T14:00Z Jane Cooper

25 Web Architecture Web architecture is: Growing in complexity Maturing, becoming more robust Must understand architecture to avoid: Escalating costs Degradation of service quality / functionality Data format Transport Address- ing Metadata

26 Information Landscapes Developments such as Web Collections will enable metadata for groups of related resources to be defined for: Providing enhanced user navigation Facilitating printing, off-line browsing,... Facilitating indexing etc. The term Information Landscapes has been coined to refer to changing, configurable views of networked resources

27 Information Landscapes Landscapes can be developed by / for: InstitutionsGroups (e.g. undergrads) Service providers... Information Landscapes can be used for delivering information based on: Institutional needs and interests End user's technologies / interface preferences Implications: Ownership, legal and copyright issues Change controlVisibility Maintenance What demand is there?

28 Using The Technologies How / when are new technologies to be deployed? Use "safe" features to ensure backwards compatibility Check for browser functionality at server Check for browser functionality at client Deploy on Intranet for access to internal resources / external resources Use tools which can regenerate systems when standards change / develop

29 WebWatch Project based at UKOLN to monitor web developments in UK Analysed various communities: University entry points eLib projects Public libraries Server software Nos. of hyperlinks File size (HTML)

30 Conclusions To conclude: Underlying web protocols continue to develop An understanding of development of the web architectures is needed to: –Exploit appropriate new developments –Avoid going in wrong direction Automated tools are essential