Basics of Website Development

Websites Overview

Website is a location on web and is hosted on a web server. It is a set of related web pages. It is accessed using Internet address known as Uniform Resource Locator

Static Websites

Static websites are also known as flat or stationary websites. They are loaded on the client’s browser as exactly they are stored on the web server. Such websites contain only static information. User can only read the information but can’t do any modification or interact with the information.

Static websites are created using only HTML. Static websites are only used when the information is no more required to be modified.

Dynamic Websites

Dynamic websites shows different information at different point of time. It is possible to change a portion of a web page without loading the entire web page. It has been made possible using Ajax technology.

Server-side dynamic web page

It is created by using server-side scripting. There are server-side scripting parameters that determine how to assemble a new web page which also include setting up of more client-side processing.

Client-side dynamic web page

It is processed using client side scripting such as javascript. And then passed in to Document Object Model (DOM).

Websites Types

Internet Forums

An internet forum is message board where people can hold conversation by posting messages.

Key Points

• A forum can contain several sub forums.
• Each of sub forums may contain a number of topics.
• Within a forum’s topic, each new discussion started is called a thread.
• This thread can be replied by as many people as so wish.

Blog

The term Blog is taken from web log. It is a kind of web site that is updated regularly, with content about almost anything. In other words, blog is aContent Management System (CMS), an easy way of publishing articles on the internet.

Blogging Terminologies

BLOG

A type of website used to publish content on the internet.

BLOGGER

A person who writes for a blog.

BLOGGING

Writing for blogs is referred as blogging.

BLOGOSPHERE

A term is used to refer all the blogs on the web.

What to Blog about

Following discussion will help you to figure out what to write about and as well as what to name your blog.

• Write what you know about. For example, if you have good computer knowledge. You can write what you know about the subject.
• You can share your experience. You can also write what you gained from that experience, what you learned.
• Detail your personal research.
• Share your memory of someone.

E-commerce

E-Commerce or Electronics Commerce is a methodology of modern business which addresses the need of business organizations, vendors and customers to reduce cost and improve the quality of goods and services while increasing the speed of delivery. E-commerce refers to paperless exchange of business information using following ways.

• Electronic Data Exchange (EDI)
• Electronic Mail (e-mail)
• Electronic Bulletin Boards
• Electronic Fund Transfer (EFT)
• Other Network-based technologies

Features

E-Commerce provides following features:

NON-CASH PAYMENT

E-Commerce enables use of credit cards, debit cards, smart cards, electronic fund transfer via bank's website and other modes of electronics payment.

24X7 SERVICE AVAILABILITY

E-commerce automates business of enterprises and services provided by them to customers are available anytime, anywhere. Here 24x7 refers to 24 hours of each seven days of a week.

ADVERTISING / MARKETING

E-commerce increases the reach of advertising of products and services of businesses. It helps in better marketing management of products / services.

IMPROVED SALES

Using E-Commerce, orders for the products can be generated anytime, anywhere without any human intervention. By this way, dependencies to buy a product reduce at large and sales increases.

SUPPORT

E-Commerce provides various ways to provide pre sales and post sales assistance to provide better services to customers.

Portfolio

Online portfolio is collection of images, multimedia, emails, blog entries, and hyperlinks that are managed online. It can be seen as a kind of learning record that provides actual evidence of achievement.

Types

There are three types of online portfolio:

1. Developmental (e.g. working)
2. Reflective (e.g. learning)
3. Representational (e.g. showcase)

Developmental portfolio contains all the things that an individual has done over a period of time.

Reflective portfolio contains personal reflection on the content.

Representational online portfolio refers to learner’s achievement in a particular work.

Website Designing

Web designing has direct link to visual aspect of a web site. Effective web design is necessary to communicate ideas effectively.

Web desinging is subset of web development. However these terms are used interchangeably.

Key Points

Design Plan should include the following:

• Details about information architecture.
• Planned structure of site.
• A site map of pages

Wireframe

Wireframe refers to a visual guide to appearace of web pages. It helps to define structre of web site, linking between web pages and layout of visual elements.

Following things are included in a wireframe:

• Boxes of primary graphical elements
• Placement of headlines and sub headings
• Simple layout structure
• Calls to action
• Text blocks

Wireframe can be created using program like Visio but you can also use a pen and paper.

Web Designing Tools

Here is the list of tools that can be used to make effective web designs:

Coda 2
Coda 2 is a powerful web development & designing tool, comes with better user interface, text editing, file management, clips, sites, design and better Mysql support.OmniGraffle
OmmniGraffle is mainly used for wireframing. The downside of this tool is that It doesnot have interactive prototyping and It is available only for Mac.Pen and Paper
Pen and paper can be used to draw the appeance of the how the web site will look like.Vim
Vim is great web desiging tool.It supports full customizable auto-intending of code, multiple buffers for storing cut/copied code, and recording of actions for automated repetition.

S.N.	Tool Description
1.	Photoshop CC This is a great web designing tool provided by Adobe. The latest Photoshop CC 2014 supports many new features such as smart objects, layer comps, smart guides, Typekit integration, font search, and workflow enhancements.
2.	Illustrator CC Illustrator CC is also a web designing tool comes with powerful features like AutoCad libraries, white overprint, fill and stroke proxy swap for text, automatic corner generation, unembed images and touch type tools etc.
3.
4.
5.	Sublime Text Sublime Text is a source code editor with Python application programming interface. It's functionality can be extended using plugins.
6.
7.
8.	Imageoptim It is basically used for optimizing images on a website in order to load them faster by finding best compression parameters and by removing unnecessary comments.
9.	Sketch 3 Sketch 3 is a web desiging tool developed specifically for designing interfaces, websites, icons etc.
10.	Heroku It is also a great web development tool which supports Ruby, Node.js, Python, java and PHP.
11.	Axure It supports prototyping, documentation, and wireframing tools for making interactive website design.
12.	Hype 2 The Hype 2 offers: Easiest way to Animate & add interactivity, Hardness the power of HTML5, Mobile responsiveness, and WYSIWYG features.
13.	Image Alpha This tool helps to reduce file sizes of 24-bit PNG files. It does so by applying lossy compression and convert it to PNG8+alpha format which more efficient.
14.	Hammer This tool is suitable for non programmers and good only for small projects.
15.	JPEGmini Lite It is an image optimizing tool and supports photos in any resolution up to 28 Megapixels.
16.	BugHerd This tool helps to see how the projects is going and what everyone is working on. It also helps to identify issues in development.

Web Page Anatomy

A web site includes the following components:

Containing Block

Container can be in the form of page’s body tag, an all containing div tag. Without container there would be no place to put the contents of a web page.

Logo

Logo refers to the identity of a website and is used across a company’s various forms of marketing such as business cards, letterhead, brouchers and so on.

Naviagation

The site’s navigation system should be easy to find and use. Oftenly the anvigation is placed rigth at the top of the page.

Content

The content on a web site should be relevant to the purpose of the web site.

Footer

Footer is located at the bottom of the page. It usually contains copyright, contract and legal information as well as few links to the main sections of the site.

Whitespace

It is also called as negative space and refers to any area of page that is not covered by type or illustrations.

Web design Mistakes

One should be aware of the following common mistakes should always keep in mind:

• Website not working in any other browser other internet explorer.
• Using cutting edge technology for no good reason
• Sound or video that starts automatically
• Hidden or disguised navigation
• 100% flash content.

Website Development

Web development

Web development refers to building website and deploying on the web. Web development requires use of scripting languages both at the server end as well as at client end.

Before developing a web site once should keep several aspects in mind like:

• What to put on the web site?
• Who will host it?
• How to make it interactive?
• How to code it?
• How to create search engine friendly web site?
• How to secure the source code frequently?
• Will the web site design display well in different browsers?
• Will the navigation menus be easy to use?
• Will the web site loads quickly?
• How easily will the site pages print?
• How easily will visitors find important details specific to the web site?
• How effectively the style sheets be used on your web sites?

Web Development Process

Web development process includes all the steps that are good to take to build an attractive, effective and responsive website. These steps are shown in the following diagram:

Web development tools

Web development tools helps the developer to test and debug the web sites. Now a days the web development tooll come with the web browsers as add-ons. All web browsers have built in tools for this purpose.

Thsese tools allow the web developer to use HTML, CSS and JavaScript etc.. These are accessed by hovering over an item on a web page and selecting the “Inspect Element” from the context menu.

Featues

Following are the common featuers that every web development tool exhibits:

HTML AND THE DOM

HTML and DOM viewer allows you to see the DOM as it was rendered. It also allows to make changes to HTML and DOM and see the changes reflected in the page after the change is made.

WEB PAGE ASSESTS, RESOURCES, AND NETWORK INFORMATION

Web development tools also helps to inspect the resources that are loaded and available on the web page.

PROFIING AND AUDITING

Profiling refers to get information about the performance of a web page or web application and Auditing provides developers suggestions, after analyzing a page, for optimizations to decerease page load time and increase responsiveness.

Skills Required

For being a successful web developer, one should possess the following skills:

• Understanding of client and server side scripting.
• Creating, editing and modifying templates for a CMS or web development framework.
• Testing cross browser inconsistencies.
• Conducting observational user testing.
• Testing for compliance to specified standards such as accessibility standards in the client region.
• Programming interaction with javaScript, PHP, and Jquery etc.

Websites Publishing

Website publishing is the process of uploading content on the internet. It includes:

• uploading files
• updating web pages
• posting blogs

Website is published by uploading files on the remote server which is provided by the hosting company.

Prerequisites for Website Publishing

In order to publish your site, you need the following things:

• Web development software
• Internet Connection
• Web Server

Web development software

It is used for building web pages for your web site. Dreamweaver and WordPress are example of web development softwares.

Internet Connection

Internet connection is required to connect to a remotely located web server.

Web Server

Web server is the actual location where your website resides on. A web server may host single or multiple sites depending on what hosting service you have paid for.

Websites URL Registration

A domain name is the part of your Internet address that comes after "www".For example, in www.freeknowledg.blogspot.in/ the domain name is freeknowledg.blogspot.in.

A domain name becomes your Business Address so care should be taken to select a domain name. Your domain name should be easy to remember and easy to type.

Domain Extensions

The final letter at end of internet address is known as top level domain names. They are called top level because they are read from right to left, and the part after the dot is the highest in a hierarchy.

The following table shows the Generic Top-Level Domain names:

Domain	Meaning
.com	Commercial Busness
.edu	Education
.gov	U.S. government agency
.int	International Entity
.mil	U.S. military
.net	Networking organization
.org	Non profit organization

Registering Domain Name

Registering a Domain Name is very simple. You can take following step to get your desired domain name registered:

• Think of a name that justifies your business need. To find out the available names you can enter a name at commercial domain name registrar such as GoDaddy.
• If the domain name entered by you is available, then select that particular domain name.
• Now it will ask you for other additional services such as Email inbox, hosting etc. that host also provides. You may choose what’s best for you.
• Now they will ask you for your personal information which is stored in WHOIS database.
• It will then ask for payment information. Pay for the purchase you have made. Make sure you enter the correct payment information.
• Once you are done with all above steps, you are ready to use their tools to upload your stuff to your site.

Domain Name Registrar

There are a number of domain name registrars available in the market.The following table contains some of popular domain name registrars:

S.N.	Domain Name Registrar
1	Address Creation, LLC
2	Addressonthe web, LLC
3	101domains, INC
4	Atomicdomainnames, LLC
5	BigRock Solutions Ltd
6	Black Ice Domain, Inc
7	Block Host LLC
8	Domain Monkeys, LLC
9	Domain Mantra, Inc.
10	DomainName, Inc.
11	Dot Holding Inc.
12	DotMedia Ltd
13	Extend Names, Inc.
14	Extremely Wild
15	Fast Domain Inc.
16	Google Inc

Websites Hosting

Overview

Web hosting is a service of providing online space for storage of web pages. These web pages are made available via World Wide Web. The companies which offer website hosting are known as Web hosts.

The servers on which web site is hosted remain switched on 24 x7. These servers are run by web hosting companies. Each server has its own IP address. Since IP addresses are difficult to remember therefore, webmaster points their domain name to the IP address of the server their website is stored on.

It is not possible to host your website on your local computer, to do so you would have to leave your computer on 24 hours a day. This is not practical and cheaper as well. This is where web hosting companies comes in.

Types of Hosting

The following table describes different types of hosting that can be availed as per the need:

S.N.	Hosting Description
1.	Shared Hosting In shared hosting, the hosting company puts thousand of website on the same physical server. Each customer has their own allocation of physical web space and a set of bandwidth limit. As all websites share same physical memory, MYSQL server and Apache server, one website on the server experiencing high traffic load will affect performance of all websites on the server.
2.	Virtual Private Server (VPS) It is also known as Virtual Dedicated Server. It is a server which is partitioned into smaller servers. In this customer is given their own partition, which is installed with its own operating system. Unlike shared hosting, VPS doesn’t share memory or processor time rather it allocates certain amount of memory and CPU to use which means that any problem on a VPS partition on the same drive will not affect other VPS customers.
3.	Dedicated Server In this kind of hosting, single dedicated server is setup for just one customer. It is commonly used by the businesses that need the power, control and security that a dedicated server offers.
4.	Reseller Hosting A reseller acts as a middle man and sells hosting space of someone else’s server.
5.	Grid Hosting Instead of utilizing one server, Grid Hosting spreads resources over a large number of servers. It is quite stable and flexible. The servers can be added or taken away from the grid without crashing the system.

Web Hosting Companies

Following are the several companies offering web hosting service:

S.N.	Hosting Company
1.	Blue Host
2.	Go Daddy
3.	Host Gator
4.	just Host
5.	Laughing Squid
6.	Hivelocity
7.	liquid Web
8.	Media TempleServInt
9.	Wired Tree
10.	Wild West Domains
11.	Wix
12.	WIPL
13.	Big Rock

Website Security Consideration

Websites are always to prone to security risks. Cyber crime impacts your business by hacking your website. Your website is then used for hacking assaults that install malicious software or malware on your visitor’s computer.

Hackers may also steal important customer data such as credit card information, destroy your business and propagate illegal content to your users.

Security Considerations

Updated Software

It is mandatory to keep you software updated. It plays vital role in keeping your website secure.

SQL Injection

It is an attempt by the hackers to manipulate your database. It is easy to insert rogue code into your query that can be used to manipulate your database such as change tables, get information or delete data.

Cross Site Scripting (XSS)

It allows the attackers to inject client side script into web pages. Therefore, while creating a form It is good to endure that you check the data being submitted and encode or strip out any HTML.

Error Messages

You need to be careful about how much information to be given in the error messages. For example, if the user fails to log in the error message should not let the user know which field is incorrect: username or password.

Validation of Data

The validation should be performed on both server side and client side.

Passwords

It is good to enforce password requirements such as of minimum of eight characters, including upper case, lower case and special character. It will help to protect user’s information in long run.

Upload files

The file uploaded by the user may contain a script that when executed on the server opens up your website.

SSL

It is good practice to use SSL protocol while passing personal information between website and web server or database.

Search Engine Optimization

What is SEO

Search Engine Optimization refers to set of activities that are performed to increase number of desirable visitors who come to your site via search engine. These activities may include thing you do to your site itself, such as making changes to your text and HTML code, formatting text or document to communicate directly to the search engine.

Types of SEO

SEO can be classified into two types: White Hat SEO and Black Hat or Spamdexing

WHITE HAT SEO

An SEO tactic, technique or method is considered as White Hat if it follows the followings

• If it conforms to the search engine's guidelines.
• If it does not involves any deception.
• It ensures that the content a search engine indexes and subsequently ranks is the same content a user will see.
• It ensures that a Web Page content should have been created for the users and not just for the search engines.
• It ensures the good quality of the web pages.
• It ensures the useful content available on the web pages.
• Always follow a White Hat SEO tactic and don't try to fool your site visitors. Be honest and definitely you will get something more.

BLACK HAT OR SPAMDEXING:

An SEO tactic, technique or method is considered as Black Hat or Spamdexing if it follows the followings:

• Try to improve rankings that are disapproved of by the search engines and/or involve deception.
• Redirecting users from a page that is built for search engines to one that is more human friendly.
• Redirecting users to a page that was different from the page the search engine ranked.
• Serving one version of a page to search engine spiders/bots and another version to human visitors. This is called Cloaking SEO tactic.
• Using Hidden or invisible text or with the page background color, using a tiny font size or hiding them within the HTML code such as "no frame" sections.
• Repeating keywords in the Meta tags, and using keywords that are unrelated to the site's content. This is called Meta tag stuffing.
• Calculated placement of keywords within a page to raise the keyword count, variety, and density of the page. This is called Keyword stuffing.
• Creating low-quality web pages that contain very little content but are instead stuffed with very similar key words and phrases. These pages are called Doorway or Gateway Pages
• Mirror web sites by hosting multiple web sites all with conceptually similar content but using different URLs.
• Mirror web sites by hosting multiple web sites all with conceptually similar content but using different URLs.
• Creating a rogue copy of a popular web site which shows contents similar to the original to a web crawler, but redirects web surfers to unrelated or malicious web sites. This is called Page hijacking.

Key Elements to ethical SEO

Keyword research

It allows you to see which keywords users actually employ to find products and services within your chosen market, instead of making guesses at the keywords you believe are the most popular.

Content development

Content development involves:

• Navigational flow and menu structure
• Site copy or articles
• Headings and sections

Web development

Web development involves:

• Text-based site development wherever possible.
• Clean and logical site structure.
• Proper markup of key page elements.

Link Building

Building links will make up about 60% of your work. There are ways to automate this process using shortcuts, workarounds, and submission services.

Internal linking is also very important. Treat the way you link to your own content same as you would link from an external site.

Webmaster Tools

Webmaster dashboard is provided by both Google and Bing that gives insight into activity by the search engine on any site that has been registered and verified via dashboard.

Dashboards offer a number of tools which allow us to understand how the search engine sees your site. These are the only way to identify crawling, indexing, and the ranking issue with your site.

SEO Do’s and Do’nts

DO's

There are various other tips which can help you to optimize your web site for many Search Engines:

• Create logs of pages and each page should however contain a minimum of about 200 visible words of text to maximize relevance with Google.
• Create a Sitemap, Help, FAQ, About Us, Link to Us, Copyright, Disclaimer, and Privacy Policy pages on mandatory basis.
• Create a home page link to each and every web page and provide easy navigation through all the pages.
• Pay attention to your dynamic page URLs. Google can crawl and index dynamic pages as long as you don't have more than 2 parameters in the URL.
• Check your complete site for broken links. Broken links will reduce your other pages rank as well.

Do'nts

Here is the list of Do'nts that one should keep in mind all the times:

• Don't keep hidden text on your web pages.
• Don't create alt image spamming by putting wrong keywords.
• Don't use Meta tags stuffing.
• Don't use frames and flash on your site.
• Don't exchange your links with black listed sites.
• Don't try to fool your site visitors by using miss spelled keywords.
• Don't send spam emails to thousand of email IDs.
• Don't use too much graphics on your site.
• Don't create too many doorway pages.
• Don't try to create duplicate content of pages.
• Don't submit your website many times in a single search engine.
• Don't use sub-directory depth more than 1-2.
• Don't create too many dynamic pages. Try to convert them into static pages.
• Don't bloat your pages with code.
• Don't nest your pages.

Website Monetization

Website monetization refers to making money from the website. It is done by converting existing traffic to a particular website into revenue.

Methods of Monetization

Display Advertising

It refers to the banners and text ads. This method is good for the websites that have significant traffic, valuable audience, relevant and active advertisers.

Affiliate Marketing

It refers to steering the visitors to products and services of a third party merchant. It is good for the websites that are product centric and have easy integration into content.

Lead generation

It refers to capturing the customer information and selling it to a third party.

Email rental

It refers to renting out your email lists to third parties. In this you will send an email on their behalf to your distribution list.

WWW Overview

Overview

WWW stands for World Wide Web. A technical definition of the World Wide Web is : all the resources and users on the Internet that are using the Hypertext Transfer Protocol (HTTP).

A broader definition comes from the organization that Web inventor Tim Berners-Lee helped found, the World Wide Web Consortium (W3C).

The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge.

In simple terms, The World Wide Web is a way of exchanging information between computers on the Internet, tying them together into a vast collection of interactive multimedia resources.

Internet and Web is not the same thing: Web uses internet to pass over the information.

Evolution

World Wide Web was created by Timothy Berners Lee in 1989 at CERN inGeneva. World Wide Web came into existence as a proposal by him, to allow researchers to work together effectively and efficiently at CERN. Eventually it became World Wide Web.

The following diagram briefly defines evolution of World Wide Web:

WWW Architecture

WWW architecture is divided into several layers as shown in the following diagram:

Identifiers and Character Set

Uniform Resource Identifier (URI) is used to uniquely identify resources on the web and UNICODE makes it possible to built web pages that can be read and write in human languages.

Syntax

XML (Extensible Markup Language) helps to define common syntax in semantic web.

Data Interchange

Resource Description Framework (RDF) framework helps in defining core representation of data for web. RDF represents data about resource in graph form.

Taxonomies

RDF Schema (RDFS) allows more standardized description of taxonomiesand other ontological constructs.

Ontologies

Web Ontology Language (OWL) offers more constructs over RDFS. It comes in following three versions:

• OWL Lite for taxonomies and simple constraints.
• OWL DL for full description logic support.
• OWL for more syntactic freedom of RDF

Rules

RIF and SWRL offers rules beyond the constructs that are available from RDFsand OWL. Simple Protocol and RDF Query Language (SPARQL) is SQL like language used for querying RDF data and OWL Ontologies.

Proof

All semantic and rules that are executed at layers below Proof and their result will be used to prove deductions.

Cryptography

Cryptography means such as digital signature for verification of the origin of sources is used.

User Interface and Applications

On the top of layer User interface and Applications layer is built for user interaction.

WWW Operation

WWW works on client- server approach. Following steps explains how the web works:

1. User enters the URL (say, http://www.tutorialspoint.com) of the web page in the address bar of web browser.
2. Then browser requests the Domain Name Server for the IP address corresponding to www.tutorialspoint.com.
3. After receiving IP address, browser sends the request for web page to the web server using HTTP protocol which specifies the way the browser and web server communicates.
4. Then web server receives request using HTTP protocol and checks its search for the requested web page. If found it returns it back to the web browser and close the HTTP connection.
5. Now the web browser receives the web page, It interprets it and display the contents of web page in web browser’s window.

Future

There had been a rapid development in field of web. It has its impact in almost every area such as education, research, technology, commerce, marketing etc. So the future of web is almost unpredictable.

Apart from huge development in field of WWW, there are also some technical issues that W3 consortium has to cope up with.

User Interface

Work on higher quality presentation of 3-D information is under deveopment. The W3 Consortium is also looking forward to enhance the web to full fill requirements of global communities which would include all regional languages and writing systems.

Technology

Work on privacy and security is under way. This would include hiding information, accounting, access control, integrity and risk management.

Architecture

There has been huge growth in field of web which may lead to overload the internet and degrade its performance. Hence more better protocol are required to be developed.

Web Pages

Web Page

web page is a document available on world wide web. Web Pages are stored on web server and can be viewed using a web browser.

A web page can cotain huge information including text, graphics, audio, video and hyper links. These hyper links are the link to other web pages.

Collection of linked web pages on a web server is known as website.There is unique Uniform Resource Locator (URL) is associated with each web page.

Static Web page

Static web pages are also known as flat or stationary web page. They are loaded on the client’s browser as exactly they are stored on the web server. Such web pages contain only static information. User can only read the information but can’t do any modification or interact with the information.

Static web pages are created using only HTML. Static web pages are only used when the information is no more required to be modified.

Dynamic Web page

Dynamic web page shows different information at different point of time. It is possible to change a portaion of a web page without loading the entire web page. It has been made possible using Ajax technology.

SERVER-SIDE DYNAMIC WEB PAGE

It is created by using server-side scripting. There are server-side scripting parameters that determine how to assemble a new web page which also include setting up of more client-side processing.

CLIENT-SIDE DYNAMIC WEB PAGE

It is processed using client side scripting such as JavaScript. And then passed in to Document Object Model (DOM).

Scripting Laguages

Scripting languages are like programming languages that allow us to write programs in form of script. These scripts are interpreted not compiled and executed line by line.

Scripting language is used to create dynamic web pages.

Client-side Scripting

Client-side scripting refers to the programs that are executed on client-side. Client-side scripts contains the instruction for the browser to be executed in response to certain user’s action.

Client-side scripting programs can be embedded into HTML files or also can be kept as separate files.

Following table describes commonly used Client-Side scripting languages:

S.N.	Scripting Language Description
1.	JavaScript It is a prototype based scripting language. It inherits its naming conventions from java. All java script files are stored in file having .js extension.
2.	ActionScriptIt is an object oriented programming language used for the development of websites and software targeting Adobe flash player.
3.	Dart It is an open source web programming language developed by Google. It relies on source-to-source compiler to JavaScript.
4.	VBScript It is an open source web programming language developed by Microsoft. It is superset of JavaScript and adds optional static typing class-based object oriented programming.

Server-side Scripting

Sever-side scripting acts as an interface for the client and also limit the user access the resources on web server. It can also collects the user’s characteristics in order to customize response.

Following table describes commonly used Server-Side scripting languages:

S.N.	Scripting Language Description
1.	ASP Active Server Pages (ASP)is server-side script engine to create dynamic web pages. It supports Component Object Model (COM) which enables ASP web sites to access functionality of libraries such as DLL.
2.	ActiveVFP It is similar to PHP and also used for creating dynamic web pages. It uses native Visual Foxpro language and database.
3.	ASP.net It is used to develop dynamic websites, web applications, and web services.
4.	Java Java Server Pages are used for creating dynamic web applications. The Java code is compiled into byte code and run by Java Virtual Machine (JVM).
5.	Python It supports multiple programming paradigms such as object-oriented, and functional programming. It can also be used as non-scripting language using third party tools such as Py2exe or Pyinstaller.
6.	WebDNA It is also a server-side scripting language with an embedded database system.

Web Browser

Web Browser

web Browser is an application software that allows us to view and explore information on the web. User can request for any web page by just entering a URL into address bar.

Web browser can show text, audio, video, animation and more. It is the responsibility of a web browser to interpret text and commands contained in the web page.

Earlier the web browsers were text-based while now a days graphical-based or voice-based web browsers are also available. Following are the most common web browser available today:

Browser	Vendor
Internet Explorer	Microsoft
Google Chrome	Google
Mozilla Firefox	Mozilla
Netscape Navigator	Netscape Communications Corp.
Opera	Opera Software
Safari	Apple
Sea Monkey	Mozilla Foundation
K-meleon	K-meleon

Architecture

There are a lot of web browser available in the market. All of them interpret and display information on the screen however their capabilities and structure varies depending upon implementation. But the most basic component that all web browser must exhibit are listed below:

• Controller/Dispatcher
• Interpreter
• Client Programs

Controller works as a control unit in CPU. It takes input from the keyboard or mouse, interpret it and make other services to work on the basis of input it receives.

Interpreter receives the information from the controller and execute the instruction line by line. Some interpreter are mandatory while some are optional For example, HTML interpreter program is mandatory and java interpreter is optional.

Client Program describes the specific protocol that will be used to access a particular service. Following are the client programs tat are commonly used:

• HTTP
• SMTP
• FTP
• NNTP
• POP

Starting Internet Explorer

Internet explorer is a web browser developed by Microsoft. It is installed by default with the windows operating system howerver, it can be downloaded and be upgraded.

To start internet explorer, follow the following steps:

• Go to Start button and click Internet Explorer.

The Internet Explorer window will appear as shown in the following diagram:

Accessing Web Page

Accessing web page is very simple. Just enter the URL in the address bar as shown the following diagram:

Navigation

A web page may contain hyperlinks. When we click on these links other web page is opened. These hyperlinks can be in form of text or image. When we take the mouse over an hyperlink, pointer change its shape to hand.

Key Points

• In case, you have accessed many web pages and willing to see the previous webpage then just click back button.
• You can open a new web page in the same tab, or different tab or in a new window.

Saving Webpage

You can save web page to use in future. In order to save a webpage, follow the steps given below:

• Click File > Save As. Save Webpage dialog box appears.
• Choose the location where you want to save your webpage from save in: list box. Then choose the folder where you want to save the webpage.
• Specify the file name in the File name box.
• Select the type from Save as type list box.
• Webpage, complete
• Web Archive
• Webpage HTML only
• Text File
• From the encoding list box, choose the character set which will be used with your webpage. By default, Western European is selected.
• Click save button and the webpage is saved.

Saving Web Elements

Web elements are the pictures, links etc. In order to save these elements follow the steps given below:

• Right click on the webpage element you want to save. Menu options will appear. These options may vary depending on the element you want to save.

Save Picture As: This option let you save the picture at specific location with its name. When you click this option, a dialog box is opened where you can sepcify its name and location.

Web Server

Overview

Web server is a computer where the web content is stored. Basically web server is used to host the web sites but there exists other web servers also such as gaming, storage, FTP, email etc.

Web site is collection of web pages whileweb server is a software that respond to the request for web resources.

Web Server Working

Web server respond to the client request in either of the following two ways:

• Sending the file to the client associated with the requested URL.
• Generating response by invoking a script and communicating with database

Key Points

• When client sends request for a web page, the web server search for the requested page if requested page is found then it will send it to client with an HTTP response.
• If the requested web page is not found, web server will the send anHTTP response:Error 404 Not found.
• If client has requested for some other resources then the web server will contact to the application server and data store to construct the HTTP response.

Architecture

Web Server Architecture follows the following two approaches:

1. Concurrent Approach
2. Single-Process-Event-Driven Approach.

Concurrent Approach

Concurrent approach allows the web server to handle multiple client requests at the same time. It can be achieved by following methods:

• Multi-process
• Multi-threaded
• Hybrid method.

Multi-processing

In this a single process (parent process) initiates several single-threaded child processes and distribute incoming requests to these child processes. Each of the child processes are responsible for handling single request.

It is the responsibility of parent process to monitor the load and decide if processes should be killed or forked.

Multi-threaded

Unlike Multi-process, it creates multiple single-threaded process.

Hybrid

It is combination of above two approaches. In this approach multiple process are created and each process initiates multiple threads. Each of the threads handles one connection. Using multiple threads in single process results in less load on system resources.

Examples

Following table describes the most leading web servers available today:

S.N.	Web Server Descriptino
1	Apache HTTP Server This is the most popular web server in the world developed by the Apache Software Foundation. Apache web server is an open source software and can be installed on almost all operating systems including Linux, UNIX, Windows, FreeBSD, Mac OS X and more. About 60% of the web server machines run the Apache Web Server.
2.	Internet Information Services (IIS) The Internet Information Server (IIS) is a high performance Web Server from Microsoft. This web server runs on Windows NT/2000 and 2003 platforms (and may be on upcoming new Windows version also). IIS comes bundled with Windows NT/2000 and 2003; Because IIS is tightly integrated with the operating system so it is relatively easy to administer it.
3.	Lighttpd The lighttpd, pronounced lighty is also a free web server that is distributed with the FreeBSD operating system. This open source web server is fast, secure and consumes much less CPU power. Lighttpd can also run on Windows, Mac OS X, Linux and Solaris operating systems.
4.	Sun Java System Web Server This web server from Sun Microsystems is suited for medium and large web sites. Though the server is free it is not open source. It however, runs on Windows, Linux and UNIX platforms. The Sun Java System web server supports various languages, scripts and technologies required for Web 2.0 such as JSP, Java Servlets, PHP, Perl, Python, and Ruby on Rails, ASP and Coldfusion etc.
5.	Jigsaw Server Jigsaw (W3C's Server) comes from the World Wide Web Consortium. It is open source and free and can run on various platforms like Linux, UNIX, Windows, and Mac OS X Free BSD etc. Jigsaw has been written in Java and can run CGI scripts and PHP programs.

Proxy Server

Overview

Proxy server is an intermediary server between client and the interner. Proxy servers offers the following basic functionalities:

• Firewall and network data filtering.
• Network connection sharing
• Data caching

Proxy servers allow to hide, conceal and make your network id anonymous by hiding your IP address.

Purpose of Proxy Servers

Following are the reasons to use proxy servers:

• Monitoring and Filtering
• Improving performance
• Translation
• Accessing services anonymously
• Security

Monitoring and Filtering

Proxy servers allow us to do several kind of filtering such as:

• Content Filtering
• Filttering encrypted data
• Bypass filters
• Logging and eavasdropping

Improving performance

It fasten the service by process of retrieving content from the cache which was saved when previous request was made by the client.

Transalation

It helps to customize the source site for local users by excluding source content or substituting source content with original local content. In this the traffic from the global users is routed to the source website through Translation proxy.

Accessing services anonymously

In this the destination server receives the request from the anonymzing proxy server and thus does not receive information about the end user.

Security

Since the proxy server hides the identity of the user hence it protects from spam and the hacker attacks.

Type of Proxies

Following table briefly describes the type of proxies:

Forward Proxies

In this the client requests its internal network server to forward to the internet.

Open Proxies

Open Proxies helps the clients to conceal their IP address while browsing the web.

Reverse Proxies

In this the requests are forwarded to one or more proxy servers and the response from the proxy server is retrieved as if it came directly from the original Server.

Architecture

The proxy server architecture is divided into several modules as shown in the following diagram:

Proxy user interface

This module controls and manages the user interface and provides an easy to use graphical interface, window and a menu to the end user. This menu offers the following functionalities:

• Start proxy
• Stop proxy
• Exit
• Blocking URL
• Blocking client
• Manage log
• Manage cache
• Modify configuration

Proxy server listener

It is the port where new request from the client browser is listened. This module also performs blocking of clients from the list given by the user.

Connection Manager

It contains the main functionality of the proxy server. It performs the following functions:

• It contains the main functionality of the proxy server. It performs the following functions:
• Read request from header of the client.
• Parse the URL and determine whether the URL is blocked or not.
• Generate connection to the web server.
• Read the reply from the web server.
• If no copy of page is found in the cache then download the page from web server else will check its last modified date from the reply header and accordingly will read from the cache or server from the web.
• Then it will also check whether caching is allowed or not and accordingly will cache the page.

Cache Manager

This module is responsible for storing, deleting, clearing and searching of web pages in the cache.

Log Manager

This module is responsible for viewing, clearing and updating the logs.

Configuration

This module helps to create configuration settings which in turn let other modules to perform desired configurations such as caching.

Search Engines

Introduction

Search Engine refers to a huge database of internet resources such as web pages, newsgroups, programs, images etc. It helps to locate information on World Wide Web.

User can search for any information by passing query in form of keywords or phrase. It then searches for relevant information in its database and return to the user.

Search Engine Components

Generally there are three basic components of a search engine as listed below:

1. Web Crawler
2. Database
3. Search Interfaces

Web crawler

It is also known as spider or bots. It is a software component that traverses the web to gather information.

Database

All the information on the web is stored in database. It consists of huge web resources.

Search Interfaces

This component is an interface between user and the database. It helps the user to search through the database.

Search Engine Working

Web crawler, database and the search interface are the major component of a search engine that actually makes search engine to work. Search engines make use of Boolean expression AND, OR, NOT to restrict and widen the results of a search. Following are the steps that are performed by the search engine:

• The search engine looks for the keyword in the index for predefined database instead of going directly to the web to search for the keyword.
• It then uses software to search for the information in the database. This software component is known as web crawler.
• Once web crawler finds the pages, the search engine then shows the relevant web pages as a result. These retrieved web pages generally include title of page, size of text portion, first several sentences etc.

These search criteria may vary from one search engine to the other. The retrieved information is ranked according to various factors such as frequency of keywords, relevancy of information, links etc.

• User can click on any of the search results to open it.

Architecture

The search engine architecture comprises of the three basic layers listed below:

• Content collection and refinement.
• Search core
• User and application interfaces

Search Engine Processing

Indexing Process

Indexing process comprises of the following three tasks:

• Text acquisition
• Text transformation
• Index creation

TEXT ACQUISITION

It identifies and stores documents for indexing.

TEXT TRANSFORMATION

It transforms document into index terms or features.

INDEX CREATION

It takes index terms created by text transformations and create data structures to suport fast searching.

Query Process

Query process comprises of the following three tasks:

• User interaction
• Ranking
• Evaluation

USER INTERACTION

It supporst creation and refinement of user query and displays the results.

RANKING

It uses query and indexes to create ranked list of documents.

EVALUATION

It monitors and measures the effectiveness and efficiency. It is done offline.

Examples

Following are the several search engines available today:

Search Engine	Description
Google	It was originally called BackRub. It is the most popular search engine globally.
Bing	It was launched in 2009 by Microsoft. It is the latest web-based search engine that also delivers Yahoo’s results.
Ask	It was launched in 1996 and was originally known as Ask Jeeves. It includes support for match, dictionary, and conversation question.
AltaVista	It was launched by Digital Equipment Corporation in 1995. Since 2003, it is powered by Yahoo technology.
AOL.Search	It is powered by Google.
LYCOS	It is top 5 internet portal and 13th largest online property according to Media Matrix.
Alexa	It is subsidiary of Amazon and used for providing website traffic information.