Introduction to Interactivity for the Web

Introduction to Interactivity for the Web

Ian GrahamTel: 978.4548

Email: [email protected]

Web: www.utoronto.ca/ian/talks/

What is Interactivity?

Two facets: Interactivity between person and

machine Interactivity between people

This talk focuses on the first of these facets

Presentation Overview

Description of types of interactivity

Some examples to illustrate types

Questions are encouraged always, at any time, about anything

Lunchtime seminar means…. Have lunch!

Interactivity and the Web

Two ways to interact with the Web

Locally -- Interact with your browser

Globally/Remotely -- Interact with something out there

Both have strengths and weaknesses and overlap

Simplest: Web Browsing

The standard way we use the Web:

Click on a hypertext link: browser goes out and retrieve a file from somewhere else, and displays it.

Initially the only type of interactivity

1. Web Browsing

It is a static interactivity

Sequences are fixed when pages are written

Viewer may choose different paths, but the pages are always the same

Browsing and Web Pages

Sd fdsa as dfsaasdf asd asd asd

asdfasd asd tasdf asfd as asdf Sd f

dsa as dfsaasdf asd asd asd

asdfasd asd tasdf asfd as asdf

























Web Server

Internet

WebBrowser



HTML/Web pages

E.g: http://www.utoronto.ca

Web Browsing

Interactivity can be either remote, or local

Remote -- pages are on a Web server Local -- pages are on a local drive, or CD-

ROM

Either is fine, if the information is static

Web Browsing advantages

It works for everyoneCan be local, or remoteCan distribute any type of data file

(HTML, Word documents, PowerPoint, etc.) Requires that the person visiting can

read these data typesBut not terribly interactive.....

2. Software on the Server

Interact with software on the Web server HTML forms, clickable images Information sent to server, for processing Server sends back results, based on

information sent.

Not static -- response depends on choices, different for each user

Server Software

Internet

WebServer



WebBrowser





























GatewayProgram

database

???

Server Software

Often called CGI programs, or Gateway programs.

Gateway between the Web server and “something else”

Example Server Programs

http://www.altavista.com ("Beaujolais Nouveau")

http://xxx.lanl.gov/find/cond-mat ( Database search tool )

Server Interaction

Interact with complex programs

Dynamically generated HTML pages

Hides resources from user harder to cheat!

Not local -- needs Web server

Browser Interaction

Several approaches Scripts in pages -- JavaScript Plugin modules Embedded Java programs

Scripting Interaction

Small “script” programs, part of the HTML document, that respond to what the user types in.

Basic interactions supported: interact with images, hypertext links,

forms

Scripting Examples

http://library.utoronto.ca

http://www.microsoft.com

Advanced Scripting Information

http://developer.netscape.com/tech/javascript/index.html?content=/docs/examples/javascript.html

http://msdn.microsoft.com/workshop/author/?RLD=70

Scripting Advantages

Local interaction Does not need Internet Does not depend on network speed

Disadvantages Local interaction Transparent to reader (can cheat, if

know how)

Current Scripting Issues

Netscape / Microsoft Incompatibility

Use two different ways of programming complex scripts “universal” scripts hard, if not impossible

New standards will help a lot

Browser Plugins

Special program to interpret data Embedded/installed on user’s computer Special formats otherwise not viewable Allows dynamic interaction with those data

Examples: http://www.utoronto.ca/ian/books/html4ed/chap2/

embed.html http://www.musicface.com

Plugin Advantages

Can process/interact with different data Streaming Audio/video Multimedia presentations Spreadsheet data, Virtual Reality

Problems Must install the plugin on all machines

Java Programs

A bit like plugins, but actually mobile programs

Download the program, run it locally

Java language makes this safe

Some Java Examples

Instructional Tools http://www.dgp.utoronto.ca/people/JamesStewart/applets/

Pure Toyshttp://www.litecom.se/java/rollerboy/

Applets -- Plus/Minuses

Run locally, and can be downloaded Can be distributed on CD-ROMS

Can be slow to download, or to run

Java compatibility problems

Mixed-Mode Interactivity

JavaScript can interact with Java applets

Java programs can interact with a remote server

Java/JavaScript can interact with plugins

Multiple Interaction Levels

WebServer

Browser





























GatewayProgram

database

???

JavaScript

JavaApplet

text

form

Other program

Summary

Interactivity on the Browser Script programs (JavaScript) Embedded plugins/objects Java applets

Interactivity on the Server Server programs, interacting with

browser user input mechanisms

Summary (2)

Client interactivity can interact with server Increased range of interaction

possibilities

More difficult to do, fewer canned tools

Introduction to Interactivity for the Web

Ian GrahamTel: 978.4548

Email: [email protected]

Web: www.utoronto.ca/ian/talks/

The End

Documents

Introduction to Interactivity for the Web