A simple view of how the applications have transformed from the past to present and how it has affected the programmers life...

1. Web Applications
Evolution of Applications
and Web….

2. Agenda
 Importance of Web in Industry
 Evolution of Applications
 Evolution of Web
 Web Applications
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3. What's the Buzz!

4. Is it really a Buzz?

5. Web market is huge and everyone wants its share

6. Applications are changing

7. Operating Systems are changing…
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8. Industries are changing…

9. Web is reaching Devices
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10. Why a shift to web?

11. Applications and Web Applications

12. Some Applications…

13. Some web pages…

14. Application and Web Page
Application
 Standalone
 Performs some functionality
 Installed binaries
 Highly interactive
Web Page
 Run in Applications (Browser)
 Displays information
 Temporary content
 Less interactive

15. Application or Web Page
Web Page
 Not installed
 Launched in Browser
Application
 Allows Chat
 Audio, video enabled
 Not just displays data
?

16. Web Applications
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Web applications
 Applications in the browser
 Applications, but not
installed
 Web pages highly
interactive
There are 2 type of Websites
• That display some stuff like
magazines (webpages)
• That allow to perform some
stuff like softwares (web
applications)

17. Application challenges
- Portability
- Extensibility
- Updating
- Easy deployment
What are the options to implement an application?
 C/ C++ exe
 C/ C++ library (static/ dynamic)
 Java classes
 Scripting languages (perl, pyhthon, javascript)

18. Implementing as Web application
Deployment
 Just a URL http://www.mathfunctions.com/factorial&n=5
Portability
 NO OS/ programming language dependency
Extensibility
 Can be used in numerous applications without changing the server module
Updating
 Any changes in server side doesn’t affect client implementations
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19. Evolution of Applications
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20. Evolution of Computers
 Computers came into
existence
 They made user’s life
easier
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 But life of developer was
hard
 Programming languages
were highly dependent on
hardware
 For same application, code
had to be re-written for
another hardware!!

21. Evolution of Operating Systems
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Operating System
HW HW HWHW
Code Code CodeCode
One
Hardware
The
Hardware
specific
Code
New
Hardware
Rewrite
Code
Code
Single
Code for all
Hardware !!

22. Hence the Applications
Applications are compiled to Native Binaries (executables)
Technologies
 C
 C++
Pros
 Can directly access system level APIs
 Fast in execution
Cons
 To maintain different application binaries for different operating systems
 Big development effort required

23. Evolution of Virtual machines
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Virtual Machine
OS OS OSOS
Code Code CodeCode
One OS
The OS
specific
Code
New OS
Rewrite
Code
Code
Single
Code for all
OS !!

24. Applications compiled for Virtual Machines
Technologies
 Java (J2SE)
 .NET
 Action Script (Flex)
 Scripting languages
 Perl, Pyhton, PHP etc.
Pros
 Single application for different OS hence easier to maintain
 Less development effort
Cons
 Target OS must have the virtual machine installed in order to execute the
application
 Slow in execution as compared to Native OS Applications
 Don’t have access to system level APIs

25. Evolution of WEB
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26. Web/ Internet
DARPA/ ARPA (Advanced Research Projects Agency)
 Defense programs during the cold war era
 Goal: Command and control network that would survive a nuclear war
 Problems: Circuit switch networks (e.g. Telephone) are vulnerable as loss of line or a
switch may hamper the communication
 Solution: Distributed, packet switched networks
The number of machines, networks and users increased dramatically after the advent of
TCP/ IP- the Internet
 TCP/IP Reference model and the protocol is the glue that holds internet together
 Growth of universal services on top of TCP/IP infrastructure (Application layer)
 E-mail
 File transfer
 Remote login
 World Wide Web (WWW)

27. Basic Web system
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28. Basic Web System - example
Google Web Server
Browser requests
a web page from
www.google.com
Generates an HTML
and sends it as
response

29. HTTP Basics
HTTP Client HTTP Server
HTTP Request
HTTP Response
• Every HTTP Request can be of following predefined HTTP
methods
•GET – download a resource
•HEAD – retrieve header information of a resource
•PUT – upload a resource to the server
•POST – submit data to be appended to a resource
•DELETE – delete a resource
• HTTP protocol consists of 2 distinct items
•HTTP Request – what the user wants to do
•HTTP Response – output of the request

30. Web (Till mid 90s)
Features
 Page metaphor
 Synchronous
 Smaller set of UI controls
 Mostly text oriented
 One way traffic, not participative
Lacked
 Rich Content
 Images
 Audio
 Video
 Interactivity

31. Page Metaphor and synchronous web
 A new HTML page is loaded on every request, like searching
something on google.com
 Which means entire content reloaded on every HTTP request.
Issues
 Most of the times, entire content need not to be updated in the web
page
 Slows down the work speed
 Looks irritating
So people felt need of Asynchronous Web!!
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32. Technologies
Client Side
 HTML – a mark up language rendered by Browsers
 Java Script – to put some logic in web pages executed by Browsers
Server Side Scripts (executed by a web server)
 ASP/ ASP .NET
 PHP
 Coldfusion
 Java via JSP
 Perl
 Pyhton
 Ruby
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33. Asynchronous Web
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Allowed websites to update data without fetching entire web page.
Impact
• Allowed fast user interactivity with web pages
• Users turned into publishers
• Personal web sites were replaced by blogs
• Birth of wikis
• Social networking websites came into existence
• User participations on web reached billion benchmark
• Web giant innovated monetizing techniques for web
• Web advertisements market

34. Technologies
Java Applets (1995)
 Allow compiled client-side code to load data asynchronously from the
web server
 Required JVM to ne installed at client machines
XMLHTTPRequest (1999)
 Fetches XML data asynchronously from web
 Invoked from java script
 Core component of AJAX
 Became widely known after used by Google in Gmail(2004) and
Google maps(2005)
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35. AJAX – Asynchronous JavaScript & XML (2005)
Only a name given to a set of tools that were already existing
 HTML and CSS for presenting
 Java script for local processing (client side functionality)
 XMLHTTPREquest object – used to send or receive data from server
asynchronously
Accepted as an official web standard in 2006 by W3C.
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36. Traditional Web system vs AJAX based Web system
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37. Traditional Web system vs AJAX based Web system
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38. Thank You
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