Web Applications

BIS4430 – unit 8

Learning Objectives

• Explain the uses of web application frameworks• Relate the client-side, server-side architecture to

dynamically generated websites• Explain the increased usability requirements for

dynamically generated websites• Compare and contrast current web applications

e.g. search engines, webmail, discussion boards

Client-server reminder

Web Application Frameworks

• Tools for developing web applications

• None are comprehensive

• System generates controlling code

• Examples– AJAX– .NET framework

AJAX

• Asynchronous JavaScript and XML

• Increases interactivity & speed

• HTML & CSS for formatting

• JavaScript for dynamically displayed information

• XML for asynchronous data exchange with the server

.NET framework

VB.NET C#

CompilerCompiler

Common Language Runtime

Common Intermediate Language

other languages……….

Dynamically generated websites

Definitions

• Pages generated by server-side scripts

• Pages that alter based on user activity

• Moving images or flash movies

When to go Dynamic?

• how will server-side scripting affect the performance of your site?

• will it affect the caching of web pages on the client side?

• how will it affect the user’s ability to bookmark pages?

• how will the url be affected? - very important wrt search engines

• will bookmarked urls return the user to the same information at a later date?

Advantages

• develop fewer pages

• automate content updates

• future-proof the site

Disadvantages

• Strain on low specification web servers

• Increased security issues

• URL change affecting search engines

• Links from external sites will need updating

DHTML

• Client-side

• Reduces load on the server

• Quicker responses

• Data storage allows multiple interactions without cookies

• Caching allows interactivity when offline

Improving your search engine results

• High number of links to your page• Keyword placement

– at the beginning of a page– repeated many times in the page– used as headings or subheadings– Alternative text for images– A summary in the noframes tag (only useful for pages in frames - see

Unit 9)

• Paid placement• http://www.wdvl.com/Location/Promotion/Search/index.html

Forums

• Essentially a user-created website

• Part of a website set aside for user interaction– Example – Oasis discussion board

• Forerunner of weblogs

Things to DO:

• Oasis+– Unit 8 – Web Applications