web technology

WE ARE GOING TO DISCUSS….

• COMMUNICATION ON THE WEB

• WEB SERVER TECHNOLOGIES

• WEB DESIGNING

• STATIC AND DYNAMIC WEB PAGES

• SCRIPTS AND TYPES OF SCRIPTING LANGUAGES

• POPULAR SCRIPTING LANGUAGES

• CASCADING STYLE SHEET

• BASIC CONCEPTS OF HTML DOCUMENTS

We rely on different websites for various purposes like…..

• Submitting online applications

• Viewing web contents

• Watching movies

• Banking transactions

• Purchase of goods through online transaction and so on.

A website is a collection of web pages.

Web pages are developed with the help of a language called

Hyper Text Markup Language(HTML). It is also a language of Internet.

A web page may contain texts, graphics, sounds, animations, and

movies.

How is this website made available on the Internet?

These web pages are to be stored in

web servers connected to the Internet, to be made available to others.

Communication on web


In order to communicate on the web, computers/devices need to understand each

other. This is made possible by making all devices follow the same protocol, namely TCP/IP.


URL is sent to DNS

server to obtain its IP

address

Browser connects to this server

using the IP address.

After process this request, the web page

to be displayed is sent to the

client.

In order to communicate on the web, computers/devices need to understand each other. This is made possible by making all devices follow the same protocol, namely TCP/IP.

Routing of a data packet from sender to a recipient

TCP breaks the data into packets

The packets travel from router to router over the

internet according to the IP

TCP reassembles the data packets back to

original form

In the Internet, there are several types of communication.

• Websites are accessed using HTTP.

• Email communication happens using SMTP.

• Internet Protocol provides the basics of communication over Internet.

The role of routers in transporting data in Internet

• The routers need not be programmed separately to handle different types of data.

• They do not need to know about the data they are transporting.

• It concerned only about the address to which the packet is to be delivered

• The openness of the data part of the packet gives the freedom to design new protocols for the Internet.

• This openness and flexibility of TCP/IP that led to the development of protocols for

– social media websites to handle messages,

– content websites to handle video and audio,

– banking websites to handle money transfer securely, etc

• It is a deciding factor for the economic success of the Internet.

Communication on the web can be categorised as

1. Client (browser) to webserver

2. Web server to Web server communication

Essential for Communication over the Internet

1. Authentication : is the process of determining whether a computer / server is the computer that it claims to be.

2. Security : it should be provided to communication over Internet so that the messages are not intercepted and modified by hackers.


• It does not usually require authentication.

• But in the case of web based banking applications / e-mail services, user names and passwords are required to be sent to the server.

• This information cannot be sent to the server in plain text due to security reasons.

• The hackers may steal usernames and passwords, if it is communicated and shared as plain text.

HTTPS (Hyper Text Transfer Protocol Secure)

• HTTPS (Hyper Text Transfer Protocol Secure) technology to encrypt the username and password and then send it to the server.

• It works using SSL (Secure Sockets Layer)

SSL (Secure Sockets Layer)

• SSL provides a standard security technology for establishing an encrypted connection between computers on Internet.

• It provides security capabilities to HTTP.

• This protocol not only ensures privacy, but also ensures that no other website can impersonate the user’s login account not alter the information sent.

• Verisign Inc. is a certification authority.

Client-Server authentication process

1. Browser requests to start a secure SSI session

2. Server returns its SSL certificate

3. Browser checks that : Certificate is valid, signed by someone user trusts. If valid, browser initiates and encrypted session

4. Server and Browser encrypts all the transmitted data.

2. Web server to web server communication

• It may be required in certain web applications.

• The web server of an online shopping website needs to send confidential information to a bank web server and vice versa.

• In such cases the web servers of the merchant and the bank are to be authenticated.

• Digital certificates –

• Payment gateway – a bridge

2. Web server to web server communication

User placing order

Merchant’s Web server

Payment gateway

Merchant bank account

Bank WS

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Server response

Request to Payment gateway

Payment gateway to response

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Web server technologies

www.dhsekerala.gov.in

Web server

• It is a server computer that hosts websites

• It enables us to deliver web pages or services like e-mail, blog etc., to users on the Internet

• It consists of a server computer that runs a server OS and a web software installed on it for providing services over the Internet

Web server

• It is a powerful computer which is always switched on and connected to a high bandwidth Internet connection

• This will facilitate Internet users around the world to access the websites and services hosted by it at any point of time

• It can have single or multiple processors, fast access RAM, high performance hard disks, Ethernet cards that supports fast communication

• It is usually installed in a data center to ensure faster Internet connectivity and redundant power supply

Data center

Data center

• It is a dedicated physical location where organisations house their servers and networking systems

• It is used for storing, processing and serving large amounts of mission-critical data to their clients

• It requires extensive backup power supply systems, cooling systems, high speed networking connections and security systems

Popular Server OS

• Linux distributions

–Redhat, openSUSE, Debian, Ubuntu, etc)

• Microsoft Windows Server

• FreeBSD

• Oracle Solaris etc.,

Web server software

• After setting up a server, a web server software has to be installed in it and configured according to the given OS

• The web server software is a program that uses the client-server model and the HTTP to ensure timely distribution of files stored in it to the users

Some of the preferred web server packages are

• Apache Server

• Microsoft Internet Information Server (IIS)

• Google Web Server (GWS)

• nginex (engine-x)

Other Software packages : FTP, e-mail, DNS, databases etc

Hardware Ports

• It is used to connect external devices to the computer

• These devices communicate with the computer using these ports

Software Ports

• It is used to connect a client computer to a server to access its services like HTTP, FTP, SMTP etc,

• To distinguish the ports, the software ports are given unique numbers

• The purpose of software ports is to identify different services like e-mail, file transfer etc, running on a single server computer

Software Ports

• Port number is a 16-bit number which when added to a computer’s IP address / URL, can be used for communicating with a particular service available on that server

• For example :

http://www.google.co.in:80

protocol Domain name

Port number

Some well-known ports and the associated services

Default Port Number

Service

20 & 21 FTP

22 SSH

25 SMTP

53 DNS

80 HTTP

110 POP3

443 HTTPS

DNS Servers

It runs a special purpose networking software that contains a database of domain names and IP addresses

DNS Servers

The DNS servers are arranged in a hierarchy. At the top level there are 13 root servers that contains name server information for all the generic top-level domains

How the DNS resolves the IP address?

1. The browser first searches it local memory (mini cache). If found, the browser uses it

2. If it is not found, it checks the OS’s local cache for the IP address

3. If it is not found there, it searches the DNS server of the local ISP

4. In the absence of the domain name in the ISP’s DNS server, the ISP’s DNS server initiates a recursive search

5. If found returns this IP address to the browser and the webpage is displayed otherwise it returns the message “Server not found” in the browser window

How the DNS searches and locates the IP address of a domain name?

Client Program

Operating System

Your ISP

Web Browser

DNS Server

DNS Resolver

Recursive DNS search

Know your progress

1. Name a protocol that works on top of the Internet Protocol(IP)

- HTTP, SMTP

2. Expand HTTPS Hyper Text Transmission Protocol Secure

3. What are the advantages of installing web servers in data centers?

To ensure faster Internet connectivity and redundant power supply, a webserver is usually installed in a data center

Know your progress

4. State whether true or false a. The web server software is a program that uses the

client-server model. True b. The web server consists of server OS and web server

software True

5. The number of bits in a software port number is _____

16 6. A Domain Name System returns the

_____________ of a domain name IP address

Know your progress

9. The social media websites developed their own protocol for communicating over the Internet. How is this possible when Internet uses TCP/IP protocol?

– The openness of the data part of the packet gives the freedom to design new protocols for the Internet.

– This openness and flexibility of TCP/IP that led to the development of protocols for social media websites to handle messages, content websites to handle video and audio, and banking websites to handle money transfer securely, etc

– It is a deciding factor for the economic success of the Internet.

Know your progress

10.The username and password of e-mail account has to be sent securely over the Internet

a. Name the technology used to send the data to the server

HTTPS

b. How does this technology support secure data communication?

HTTPS works using SSL (Secure Sockets Layer). SSL provides a standard security technology for establishing an encrypted connection between computers on Internet.

Know your progress 11.ABC Engineering College has about 1000 computers

connected to the Internet, in its campus. What is the advantage of having a local DNS server in the college’s intranet?

This local DNS server contains a list of domain names and their IP addresses which the users in the organisation regularly access. This list can be updated periodically to include new domain names.

Whenever a computer in the intranet tries to access a website in the Internet, it first searches for the domain name in the local DNS server and finds the IP address. This speeds up the Internet access in the organisation. Only if the domain name is not found in the local DNS server, it searches the DNS of ISP

Know your progress 12.Write an example of a web server OS and a web

server package

Linux distributions (Redhat, openSUSE, Debian, Ubuntu, etc)

Microsoft Windows Server

FreeBSD

Oracle Solaris etc.,

13.What is the use of software ports in a web server?

To identify different services like e-mail, file transfer, etc., running on a single server computer.

Know your progress 13.The port used for HTTP is ________

80

14.Suppose you are browsing the website www.prdkerala.org . Explain how DNS resolves the IP address.

http://www.prdkerala.org/





Web Designing

The first step in setting up a website is planning the web pages

for the websites

Popular web designing softwares

Bluefish

Bootstrap

Adobe Dreamweaver

Microsoft Expression web

HTML

• Hyper Text Markup Language

• It consists of tags and its attributes used to format web pages

Static web pages

• Web pages that remain the same all the time until their code is changed manually.

• It is created using HTML.

Dynamic web pages

• The web pages that contain server side code which creates a web page each time it is accessed are called dynamic web pages.

• Program code that runs on the server is called server side code.

• Technologies like PHP, ASP, JSP, etc., are used to develop dynamic web pages

Comparison of static and dynamic web pages

Static web page

• The content and layout of web page is fixed

• It never use databases

• It directly run on the browser and do not require any server side application program

• These are easy to develop

Dynamic web page

• The content and layout may change during run time

• It uses the databases to generate dynamic content through queries

• It runs on the server side application program and displays the results

• This web page development requires programming skills

scripts

• These are program codes written inside HTML page.

• They are written using a text editor like notepad.

• Scripting languages like JavaScript, VB script, PHP, Perl, etc., are used to create dynamic web pages.

scripts • In an HTML page, a script is written inside <SCRIPT>

and </SCRIPT> tags.

• <SCRIPT> is used to embed or refer to an executable script within an HTML docment.

• It has the attributes type and src.

• Type attribute is used to identify the scripting language code embedded within the script tag

• Src attribute is used to specify the URL of an external file containing scripting code to be linked to a web page.

• <SCRIPT type = “text/javascript” src = “scriptcode.js”>

Types of scripting languages

1. Client Side scripting

2. Server Side scripting

Client Side scripting • It is used to perform any task at the client side

and is executed in the browser.

• Since the script code is executed on the client browser, it provides a quick response to the users.

• Disadvantage: there are browsers that do not support scripts. In some cases users may turn off the execution of scripts in the browser.

• Eg. JavaScript, VB script

• It is mostly used for validations and also for performing simple calculations

Server Side scripting

• It is used to create dynamic web pages and are executed in the server.

• Since the scripts are executed at the sever, the type and version of the browser or OS on the client’s computer does not affect its execution.

• Eg. Perl, PHP, ASP, JSP etc.,

Working of server side scripts

MySQL Database

Web Server softwares

PHP

CLIENT

SERVER

1

2 3 4

Working of server side scripts

1

2

3

4

The web page containing server side scripts requested by the user

Server side scripts which executes and access the result from the database

Creates simple web pages dynamically

This web page is then sent to the client browser and the browser displays it

Comparison of the classifications of scripting languages

Client side scripting • Script is copied to the client

browser and executed in the client browser

• Client side scripts are mainly used for validation of data at the client

• Users can block client side scripting

• The type and version of the web browser affects the working of a client side script

Server side scripting • Script remains in the web

server and is executed in the web server and the web page produced is returned to the client browser

• Server side scripts are usually used to connect to database and return data from the web server

• Server side scripting cannot be blocked by the user

• The features of the web browser does not affect the working of server side script

Scripting Languages

• Some of the popular scripting languages are given below:

1. JavaScript

2. VB Script

3. PHP (Hypertext PreProcessor)

4. ASP (Active Server Pages)

5. JSP (Java Server Pages)

1. JavaScript • It is a client side scripting

language used to make web pages interactive

• It was developed by Brendan Eich while he was working for Netscape Communications Corporation

• It is implemented as an interpreted language

• Any text editor such as Geany IDE, notepad etc, can be used to write JavaScript code

JavaScript

• It is popular as a client side scripting tool and works in almost every browser

• It can be inserted inside HTML code or can be written as an external file and then included inside HTML file

• The extension name javaScript file is .js

• It is a tool for validation of forms in the client side and also be used for performing simple calculations and also for bringing animations to a web page

Ajax

• It is the technology used in JavaScript

• Ajax is Asynchronous JavaScript and Extensible Markup Language(XML) and XML is a markup language which helps users to create new tags

• It improves the interactivity of the browsers

Advantage of using Ajax

1. After implementing Ajax on a website, it does not require the entire page to be reloaded for displaying dynamic content on web pages

2. It allows web pages to be updated by exchanging small amounts of data between the client and the server behind the scenes

Since Ajax relies more on JavaScript, if the browser is not capable of

handling JavaScript or user has turned off JavaScript functionality in the

browser, the Ajax application will not work

2. VB Script • It is a scripting language developed by Microsoft

Corporation based on the popular programming language Visual Basic.

• It was developed to used either as a client side scripting language for Microsoft IE or as a server side scripting language with the Microsoft IIS.

• Browsers other than IE may not be able to correctly interpret and display the VB script code. Therefore it is less popular as a client side scripting tool.

• It is popular for server side scripting.

• VBScript as a part of ASP.NET in .NET framework

3. PHP • It stands for ‘PHP : Hypertext Pre-Processor’.

• It is an open source general-purpose scripting language that is suited for web development.

• It can be embedded into HTML code.

• It is a server side scripting tool and its code is similar to Java, C and PERL.

• Its main objective is to develop dynamic web pages at ease.

PHP

• It was originally created by Rasmus Lerdorf in 1994 but it is now developed by The PHP Group.

• The web page files that contain PHP code have the extension .php

PHP • PHP code is inserted inside HTML code and

when the user request for PHP web page, it is interpreted and executed on the web server.

• One of the strongest and most significant features in PHP is its support for database programming.

• The most common database used with PHP is MySQL.

Both server softwares are freely downloadable.

4. ASP

• It is a server-side scripting environment that can be used to create and run interactive web applications.

• It contains HTML and scripting languages (VBScript, JavaScript).

• ASP files have the extension .asp

• These files are compiled using the Microsoft’s web server software, IIS (Internet Information Server).

• It is executed only on Windows OS

5. JSP • This technology provides a simple and fast way to

create dynamic web content .

• It is a server side scripting language that was developed by Sun Microsystems in 1999 .

• It is similar to PHP, but uses Java as programming language

• JSP files have the extension .jsp

• To run JSP, Apache Tomcat web server is required.

• It is an integral part of Java 2 Platform Enterprise Edition (J2EE) .

Cascading Style Sheet (CSS)

• It is a style sheet language used for describing the formatting of a document written in HTML.

• Using CSS, we can control

– The colour of the text,

– The style of fonts,

– The spacing between paragraphs,

– How columns are sized and laid out, borders and its colours,

– What background images or colours are used, as well as a variety of other effects in a web page.

CSS can be implemented in three different ways

• In inline style, the CSS style is applied to each tag separately using the style attribute in the body part of the web page.

• Embedded CSS codes are placed within the <HEAD> part of the web page.

• Linked CSS implementation is done using an external file with the file extension .css that contains only CSS code and is linked with the web page.

Advantage of CSS

• We can reuse the same code for all the pages.

• Since CSS styles are written in a common place, it separates CSS and HTML, which makes it easy for maintenance.

• It is easy to understand.

• This also reduces the size of the web page thereby providing faster downloads for web pages.

Know your progress 1. The web pages that remain the same until their code is

changed manually are called _______.

– Static web pages 2. Name two technologies that can be used to develop

dynamic web pages .

– JSP, PHP, ASP 3. The tag used to embed scripts is _______ .

– <SCRIPT>……</SCRIPT> 4. Write any one of the uses of client side scripting.

It is used to perform any task at the client side and is executed in the browser. Since the script code is executed on the client

browser, it provides a quick response to the users.

Know your progress 5. A JavaScript file has the extension______ .

– .js 6. What is the advantage of using Ajax?

– After implementing Ajax on a website, it does not require the entire page to be reloaded for displaying dynamic content on web pages

– It allows web pages to be updated by exchanging small amounts of data between the client and the server behind the scenes

7. Classify the following scripting languages into client side and server side.

JavaScript, PHP, ASP, VBScript Client side : JavaScript Server side : PHP, ASP, VBScript

Know your progress 8. .asp files are compiled using the web server

software __________ . – IIS (Internet Information Server)

9. List the different ways of implementing CSS – In inline style, the CSS style is applied to each tag

separately using the style attribute in the body part of the web page.

– Embedded CSS codes are placed within the <HEAD> part of the web page.

– Linked CSS implementation is done using an external file with the file extension .css that contains only CSS code and is linked with the web page.

Know your progress 10.What are the advantages of CSS?

– We can reuse the same code for all the pages.

– Since CSS styles are written in a common place, it separates CSS and HTML, which makes it easy for maintenance.

– It is easy to understand.

– This also reduces the size of the web page thereby providing faster downloads for web pages.

Basic concepts of HTML documents

• the most widely used language to write web pages.

• It is not a Programming Language.

• It is not a Case Sensitive Language.

• Each HTML file is a plain text that defines a set of commands for creating hypertext documents. These commands are known as HTML tags.

HTML (Hyper Text Markup Language)

• Developed originally by Tim Berners – Lee in 1980 at CERN, a European Particle Physics Laboratory.

• Now HTML standards are controlled by W3C an organisation founded in 1994.

• The HTML files must be saved with .htm or .html extensions.

• HTML pages are viewed with the help of a software called Web Browsers.

• Popular Web Browsers are

– Microsoft Internet Explorer

– Mozilla Firefox

– Google Chrome

– Opera etc.,

TAGS

Tags are generally classified into two types : 1. Container tag

2. Empty tag

Container tag or element

• This type of html tag or elements require pair tags, ie., a starting tag as well as an ending tag.

• Examples :

<html>…….. </html>

<head>……</head>

<title> …………….</title>

<body>……….</body>

Empty tag or element

• This type of html tag or elements require just a starting tag and not an ending tag.

• Examples :

<br>

<frame>

<hr>

<img> etc.,

Attributes

An attribute is a special word used inside the tag to specify additional

information such as colour, alignment, background etc.,

Examples :

bgcolour, background, type, align etc.,

Basic structure of HTML document

Example of HTML document

<html>

<head>

<title> This is the title of web page </title>

</head>

<body>

Hello, Welcome to the world of web pages !

</body>

</html>

<html> tag

• It indicates that the document begins with <html> tag and ends with </html> tag.

• DIR attribute :

• It is used to indicate the document direction.

• It can take two values “ltr” and “rtl”.

• It specifies whether the language direction is from left to right or right to left.

• Example : <html dir = “ltr”>

<html> tag

• LANG attribute :

• It specifies the language to be used in the web page.

• Example :

<html lang = “en”>

Code Language

en English

fr French

de German

it Italian

el Greak

es Spanish

ar Arabic

ja Japanese

hi Hindi

ru russian

<head> tag

• It contains the head of an HTML document, which holds information about the document such as its title, scripts used, style definitions etc.,

• It is also a container tag.

<title> tag

• It is also a container tag pair that contains the title of the HTML document, which will appear in the web browser’s title bar.

• The search engines uses the Title to identify the page.

• It is used inside the tag pair <head>..</head>

<body> tag

• It is also a container tag pair that specifies the document body section.

• This part contains the content to be displayed in the browser window.

• Some attributes of <body>..</body> tag

• Background, bgcolour, text, link, alink, vlink, leftmargin, topmargin etc.,

background

• It is an attribute of <body> tag.

• It sets an image as background for the documents body.

• It makes the page more attractive.

• General format :

• <body background = “URL of the picture”>

• Example:

• <body background = “school.jpg”>

To set an image as background for a web page.

<html>

<head>

<title> Background Image </title>

</head>

<body background = “school.jpg”>

<H1> BEM HIGHER SECONDARY SCHOOL PALAKKAD </H1>

</body>

</html>

bgcolor

• It is an attribute of body tag.

• It specifies a colour for the background of the document body.

• The value of bgcolor attribute can be given in two ways: Color_name and Hex_number

• Example :

• <body bgcolor = “blue”>

text

• It is an attribute of body tag.

• It specifies the colour of the text content in the page.

• By default the browser displays the text in black colour on a white or grey background.

• The value of text attribute can be given in two ways: Color_name and Hex_number

• Example :

• <body text = “red”> or <body text = “#ff0000”>

Link, alink and vlink

• A hyperlink is an element, a text or an image that we can click on, and jump into another document or another section of the same document.

• A hyperlink points to a whole document or to a specific element within a document.

• link, alink and vlink are attributes of body tag

• Link : it specifies the colour of the hyperlinks that are not visited by the viewer. The default colour is blue.

• Alink : it specifies the colour of the active hyperlink. The link remains active only for the moment the mouse is clicked on it. The default colour is green.

• Vlink : it specifies the colour of the hyperlink which is already visited by the viewer. The default colour is purple.

Leftmargin and Topmargin

• Leftmargin : it is used to leave some blank area on the left side of the document. The value is specified in pixels.

• Topmargin : it is used to leave some blank area at the top edge of the document window. The value is specified in pixels.

• For example :

<body leftmargin = “60” topmargin = “70”>

Know your progress

1. HTML stands for _______.

– Hyper Text Markup Language.

2. What is container tag ?

– Tags that require opening tag as well as closing tag are known as container tag.

– Eg. <html>…</html>

3. The type of tag that requires only a starting tag but not an ending tag is called _______.

– Empty tag

4. State true or false – Tags are case sensitive. – FALSE – Bgcolor is an attribute of <BODY> tag. – TRUE – <TITLE> tag is an empty tag. – FALSE – Dir is an attribute of <HEAD> tag. – FALSE

5. Name the attributes of <HTML> tag. – Dir, Lang – Eg. <html Dir=“ltr” Lang=“en”>…</html>

6. What is the use of attributes in a tag? – To provide additional information such as colour, measurement,

location, alignment or other appearances to the web browser.

7. List the different attributes of <BODY> tag. – Bgcolor, background, text, topmargin, leftmargin, link, vlink, alink

Some common tags

• Used for formatting the text contents in the body section of the HTML document and therefore they are called formatting tags.

1. HEADING TAGS <H1> to <H6>

– Main attribute of this tag is align.

– The possible values are left, right, center.

– Eg. <H1 ALIGN = “LEFT”> HEADER-1 </H1>

2. Creating paragraphs - <P> tag – It indicates a new paragraph and instructs the

browser to add a blank line before the paragraph.

– It is a container tag <P>……..</P>

– Main attribute of this tag is align.

– The possible values are left, right, center, justify.

– Eg. <P ALIGN = “LEFT”> paragraph content </P>

3. Inserting line break - <BR> tag – It is used to break the current line of text and

continue from the beginning of the next line.

– It is a empty tag <BR> i.e., no ending tag.

4. Creating horizontal line - <HR> tag

– It produces a horizontal line spread across the width of the browser window.

– It is a empty tag <HR>

– Main attribute of this tag is align, size, width, color, noshade.

– The possible values for align attribute are left, right, center.

– Eg. <HR SIZE = “10” WIDTH = “50%” ALIGN = “CENTER” COLOR = “GOLD” NOSHADE >

5. Centring the content - <CENTER> tag

– It brings the content to the centre of a web page horizontally.

– The content may be text, image, table etc.,

– It is a container tag <CENTER> ……</CENTER>

– There is no attribute for this tag.

6. Text formatting tags

– <B> - it sets the text style to bold. <B>….</B>

– <I> - it sets the text style bold italics. <I>….</I>

– <U> - it is used to underline a text in HTML. <U>….</U>

– <S> and <STRIKE> - it sets the text in strike through style. <STRIKE>….</STRIKE>

– <BIG> - it is used to make the content bigger in size than the normal text size. <BIG>….</BIG>

– <SMALL> - it is used to make the content smaller in size than the normal text size. <SMALL>….</SMALL>

– <STRONG> - it is just the same as <B> <STRONG>….</STRONG>

– <EM> - it sets the text style italics. It is the same as that of <I> <EM>….</EM>

– <SUP> - it is used to create supscripts in a web page. <SUP>….</SUP>

– <SUB> - it is used to create subscripts in a web page. <SUB>….</SUB>

– <BLOCKQUOTES> and <Q> - it is used to indent the content enclosed in these tags. <BLOCKQUOTES>….</BLOCKQUOTES>

Know your progress

1. Name some of the text formatting tags. – <B>…</B>

– <I>…</I>

– <U>…</U>

– <STRIKE>…</STRIKE>

– <BIG>…</BIG>

– <SMALL>…</SMALL>

– <STRONG>…</STRONG>

– <EM>…</EM>

– <SUB>…</SUB>

– <SUP>…</SUP>

– <BLOCKQUOTE>…</BLOCKQUOTE>

2. List the different attributes of <HR> tag. – SIZE, WIDTH, ALIGN, COLOR, NOSHADE

3. How many levels of heading tags are available in HTML? – Six levels

– <H1>..</H1>

– <H2>..</H2>

– <H3>..</H3>

– <H4>..</H4>

– <H5>..</H5>

– <H6>..</H6>

4. Write an HTML code segment to display X⁴ + Y⁴. – X <SUP> 3 </SUP> + Y <SUP> 3 </SUP>

5. State True or False. – <BR> tag is an empty tag –

– TRUE

– <EM> and <I> tags have same usage in HTML document. –

– TRUE

– <U> and <I> tags are not allowed to be used together. –

– FALSE.

6. What is the use of <STRONG> tag? – it sets the text style Bold. It is the same as that of <B>

7. Pick the odd one out from the following – HTML, ALIGN, HEAD, CENTER

– ALIGN

<PRE> - Displaying preformatted text

• It is used to display the content as we entered in the text editor.

• It turn off the automatic formatting applied by the browser.

• It is a container tag.

• <PRE>………..</PRE>

<ADDRESS> - Displaying the address

• It defines the contact information for the author / owner of document or an article.

• Most of the browsers display the texts in italics.

• It is a container tag.

• <ADDRESS>………..</ADDRESS>

<MARQUEE> - Displaying text in a scrolling Marquee

• It displays a piece of text or image scrolling horizontally or vertically in the web page.

• It is a container tag.<MARQUEE>...</MARQUEE>

• The list of important attributes of <MARQUEE>.

– HEIGHT, WIDTH, DIRECTION, BEHAVIOUR, SCROLLDELAY, SCROLLAMOUNT, LOOP, BGCOLOR, HSPACE, VSPACE

<DIV> - Formatting a block of text

• It is used for defining a section or a block in the document.

• It is a container tag.<DIV>...</DIV>

• The list of important attributes of <DIV>.

– ALIGN, ID, STYLE

<FONT> - Specifying font characteristics

• It allows us to change the size, style and colour of the text enclosed within this tag.

• It is a container tag.<FONT>...</FONT>

• The list of important attributes of <FONT>.

– COLOR – it sets the text colour

– FACE – it specifies font face i.e., type

– SIZE - it specifies the font size whose values ranges from 1 or 7, with default value 3.

HTML entities for reserved characters • a few special characters and their equivalent entities.

Character Entity Description

Non Breaking Space

“ " Double quotation mark

‘ ' Single quotation mark

& & Ampersand

< < Less than

> > Greater than

© © Copyright Symbol

™ &trade Trademark Symbol

® ® Registered Symbol

Adding comments in HTML document

• HTML provides comment tag to insert comments in the source code.

• HTML comments are placed within  tag.

• It will be completely ignored by the browser.

Inserting images • <IMG> tag is used to insert images in HTML pages.

• It is an empty tag and it has many attributes.

• SRC is the main attribute and it specifies the file name of the image to be inserted.

• Other attributes are WIDTH, HEIGHT, VSPACE, HSPACE, ALIGN, BORDER, ALT

• The possible values for ALIGN attribute are BOTTOM, MIDDLE, TOP

• <IMG SRC=“book.jpg” HEIGHT=“40” WIDTH =“60” ALIGN = “BOTTOM” ALT=“Image of an opened book”>

Know your progress 1. How are special characters represented in

HTML? – HTML entites

2. Face attribute is used with ______ tag. – <FONT> TAG

3. List the attributes of <FONT> tag. – FACE, SIZE, COLOR

4. What is the use of <PRE> tag? – It is used to display the content as we entered in the

text editor.

5. For scrolling a text, we use ________ tag. – <MARQUEE>

6. What are the main attributes of <MARQUEE> tag? – HEIGHT, WIDTH, DIRECTION, BEHAVIOUR,

SCROLLDELAY, SCROLLAMOUNT, LOOP, BGCOLOR, HSPACE, VSPACE

7. What is the use of <ADDRESS> tag? – It defines the contact information for the author /

owner of document or an article.

8. What is the normal font size in <FONT> tag? – 3

9. Name the main attributes of <DIV> tag. – ALIGN, ID, STYLE

10.To insert images in an HTML document ______ is used. – <IMG> TAG

11._________ is the main attribute of <IMG> tag. – SRC

12.What is the use of ALT attribute of <IMG> tag? – To specify an alternate text for an image

13.Name the attributes that are used to display an image in a particular size. – WIDTH, HEIGHT

14.Which are the attributes that provides horizontal and vertical spaces between two images? – HSPACE, VSPACE

15.Who developed HTML?. – Tim Berners Lee

16.In HTML, there are mainly two sections. Can you name them? – Head section and Body section

17.The default colour of the attribute ALINK is ___. – GREEN

18.The default colour of the attribute VLINK is ___. – PURPLE

19.Name the tag which has NOSHADE attribute. – <HR> tag

20.The default alignment of an image obtained by using <IMG> tag is ______. – BOTTOM