Introduction ITM-711 Web Applications

2 Outline  Overview of The Web  Good Design

The web in perspective World Wide Web (WWW) At CERN (the scientific research laboratory near Geneva, Switzerland) In 1990, Tim Berners-Lee presented a proposal for an information management system that would enable the sharing of knowledge and resources over a computer network. On 30 April 1993, CERN announced that the World Wide Web would be free to use for anyone.

The web in perspective In 1994 Tim Berners-Lee decided to constitute the World Wide Web Consortium (W3C) –Regulate the further development of the many technologies in a standardization process: HTTP HTML etc. The following years saw an exponential growth of the number of web sites and servers

5 WWW  is an information space in which the items of interest (resources) are identified by Uniform Resource Identifiers (URI)

6 WWW 

7 Architecture  The web architecture has three bases: Identification - URI Interaction - messages + data + protocols Representation - data format specification

8 Two-Tier Client/Server Architecture Two-tier client/server architecture has one client and one server

9 Web Server Software  The most popular Web Server programs are: Apache Internet Information Server (IIS)

10 Application Script  Server-Side Script install on web server/application CGI, ASP, ASP.NET, PHP  Client-Side Script install on client terminals JavaScript, VBScript

11 Web Authoring Tools  Text Editor Notepad Editplus WordPad HomeSite

12 Web Authoring Tools  WYSIWYG Macromedia Dreamweaver Microsoft FrontPage NetObject Fusion

13 Good Design  Structure the web site is structured sensibly if the structure is not clear, users will not be able to navigate to the information in which they are interested

14 Good Design  Common used techniques for aiding navigation given an index at the top of the page provide a set of buttons at the top and buttom design a way in which the user can get back when you provide a hyperlink the use of frames or tables

15 Good Design  Table VS Frames VS... Frame: - simple - provide excellent navigation - take up space on the visitor’s screen for borders and scrollbars

16 Good Design  Table VS Frames VS... Table: - makes the design of the page much more complex

17 Good Design  Table and Frames Comparison Frames: - need multiple source files - code is easy to read and it is clear where any piece should go - writing the code is time consuming(but not too difficult) - easy to add new pages or new sections to your site

18 Good Design  Table and Frames Comparison Frames: - each frame can be scrolled independently - border can look messy - screen can look cluttered

19 Good Design  Table and Frames Comparison Tables: - a single source file - code can be confusing - coding for tables can be very difficult and is not easily maintained - changing the structure of the site involve a major re-write of the code

20 Good Design  Table and Frames Comparison Tables: - no borders are used - a very clean look

21 Good Design  Five components which must be considered when creating a Web site: Learnability Efficiency Memorable Errors Satisfaction