tag. 4. Write a CSS file to define font type, style and size to

tag. Part – IV Answer to the following questions (5 Marks): 1. Write an HTML document to display the following paragraph as per the given description Using CSS: • Font Name : Cooper Black • Style : Bold Italics • Color : Blue “The State Institute of Education (SIE) was established in 1965 to provide for systematic study of problems relating to School Education under the istration of Directorate of School Education.” 2. List and explain the Font and text element properties and values used CSS. GLOSSARY Style Sheet

-

A separate file contains the style of appearance.

Selector

-

An HTML element

Property

-

Attribute of an HTML tag

Link

-

Connecting with another file

References: • Mastering HTML, CSS & JavaScript Web Publishing – Laura Lemay, Rafe Colburn, Jennifer Kyrnin – BPB Publications. • Informatics Practices, A text book for CBSE class XII – SumitaArora – DhanpatRai& Co. • Computer Application (Commerce) – Text book of XII – Department of Education – SCERT, Kerala. • https://www.w3schools.com/html/default.asp 126

Chapter 13 Pages 116-126.indd 126

02/08/18 2:48 PM

www.tn11th.in

Unit IV

JavaScript

CHAPTER

14

Introduction to JavaScript Learning Objectives: • To understand about JavaScript Language and advantages of JavaScript • To understand the importance of Client side code, Steps to follow to JavaScript Programs. • To understand JavaScript Variables, Declaring Variables and Rules for naming Variables – Scope of Variables and asg values to variables. • To develop the skills of Web page development using HTML and CSS • To acquire the skills of web scripting using JavaScript • To develop the skills of Internet and Online applications

14.1 Introduction to JavaScript:

On December 4, 1995, Netscape and Sun Inc. tly introduced JavaScript 1.0. JavaScript had truly bridged the gap between the simple world of HTML and the more complex Common Gateway Interface (CGI) programs on the Server. It provides a common scripting language for Web developers to design, test and deploy Internet Applications.

The JavaScript client-side technology provides many advantages over traditional CGI Server-side scripts. For example, JavaScript code can be used to check if the has entered a valid e-mail address in a form field. The JavaScript code is executed when the click Submit button in the form, and only if all the entries are valid, they would be submitted to the Web Server.

14.2 Advantages of JavaScript Programming Language • In HTML chapter we have learnt how to develop static web pages. But in real life web pages must be interactive. So to develop such interactive pages (Dynamic Web page ) JavaScript programming language is used. • entered data in the Dynamic Web page can be validated before sending it to the server. This saves server traffic, which means less load on your server. 127

Chapter 14 Pages 127-153.indd 127

02/08/18 2:49 PM

www.tn11th.in • JavaScript includes such items as Textboxes, Buttons, drag-and-drop components and sliders to give a Rich Interface to site visitors. For example Creating a New email in any service provider.

14.3 Using JavaScript in HTML page with <script> tag : JavaScript can be implemented using <script>... tags. The <script> tag containing JavaScript can be placed anywhere within in the web page, but it is normally recommended that should be kept it within the tags. The <script> tag alerts the browser program to start interpreting all the text between these tags as a script commands. The syntax of JavaScript segment in Hyper Text Markup Language (HTML) or Dynamic Hyper Text Markup Language (DHTML) is as follows:

<script language="javascript" type="text/javascript">



JavaScript code

The <SCRIPT> tag takes two important attributes − Language − This attribute specifies that the scripting language. Typically, its value will be javascript. Although recent versions of HTML (EXtensible HyperText Markup Language XHTML, its successor) have phased out the use of this attribute is optional. Type − This attribute is used to indicate the scripting language and its value should be set to "text/javascript". 14.3.1 Steps to follow to code JavaScript Language • Enter HTML and JavaScript code using any text editor. • Save the latest version of this code. • Use any browser to see the result. For example : Internet Explorer, Google Crome, etc., • If this is a new document, open the file via browser's Open Menu. If the document is already loaded in the Memory, to reload the file into the browser use "Refresh" or press F5 button.

128

Chapter 14 Pages 127-153.indd 128

02/08/18 2:49 PM

www.tn11th.in 14.3.2 First JavaScript Program Illustration 14.1 Simple JavaScript Program

<Title>My First JavaScript Program



<script language="javascript" type="text/javascript">



document.write("Hello World!")

Output:

14.4 Lexical Structure of a JavaScript Program The lexical structure of a programming language is the set of elementary rules that specifies how to write programs in that language. It is the lowest-level syntax of a language. The Lexical structure specifies variable names, the delimiter characters for comments, and how one program statement is separated from the next. • Though JavaScript is a case-sensitive language. It is good programming practice to type the command in lowercase. • JavaScript ignores spaces that appear between tokens (identifiers, operators, punctuator, constants and keywords) in programs. 129

Chapter 14 Pages 127-153.indd 129

02/08/18 2:49 PM

www.tn11th.in • JavaScript s two styles of comments. Any text follow a “//” and the end of a line is treated as a single line comment and is ignored by JavaScript. Any text between the characters “ /* */” is also treated as a multiline comment. • JavaScript uses the semicolon (;) to separate statements. Many JavaScript programmers use semicolons to explicitly mark the ends of statements. • A literal is a data value for variable that appears directly in a program. • An identifier is simply a name. In JavaScript, identifiers are used to name variables, functions and to provide labels for certain loops in JavaScript code. • In JavaScript certain keywords are used as reserved words, These words cannot used as identifiers in the programs

14.5 JavaScript Variables: Variable is a memory location where value can be stored. Variable is a symbolic name for a value. Variables are declared with the var keyword in JavaScript. Every variable has a name, called identifier. 14.5.1 Basic Data types and Declaring variables: Every variable has a data type that indicates what kind of data the variable holds. The basic data types in JavaScript are Strings, Numbers, and Booleans. • A string is a list of characters, and a string literal is indicated by enclosing the characters in single or double quotes. Strings may contain a single character or multiple characters, including whitespace and special characters such as \n (the newline). • Numbers can be integer or floating-point numerical value and numeric literals are specified in the natural way. • Boolean can be any one of two values: true or false. Boolean literals are indicated by using true or false directly in the source code. Variables are declared in JavaScript using var keyword that allocates storage space for new data and indicates to the interpreter that a new identifier is in use. Declaring a variable in JavaScript as follows:

var no; var no1,no2;

The var no; statement tells the interpreter that a new variable no is about to be used and var no1,no2; tells the interpreter that no1 and no2 are variables. 130

Chapter 14 Pages 127-153.indd 130

02/08/18 2:49 PM

www.tn11th.in 14.5.2 Rules for naming variable 1. The first character must be a letter or an underscore (_). Number cannot be as the first character. 2. The rest of the variable name can include any letter, any number, or the underscore. You can't use any other characters, including spaces, symbols, and punctuation marks. 3. JavaScript variable names are case sensitive. That is, a variable named Number is treated as an entirely different variable than one named number. 4. There is no limit to the length of the variable name. 5. JavaScript's reserved words cannot be used as a variable name. All programming languages have a supply of words that are used internally by the language and that cannot be used for variable names. 14.5.3 Scope of variables

The scope of a variable is the life time of a variable of source code in which it is defined.

• A global variable has global scope; it can be defined everywhere in the JavaScript code. • Variables declared within a function are defined only within the body of the function. They are local variables and have local scope. 14.5.4 Asg values to variables Variables can be assigned initial values when they are declared as follows:

var numericData1 = 522;



var stringData = "JavaScript has strings\n It sure does";



var numericData = 3.14;



var booleanData = true;

131

Chapter 14 Pages 127-153.indd 131

02/08/18 2:49 PM

www.tn11th.in

Illustration 14.2 Declaring Variables

<Title>Demo Program - Declaring Variables in JavaScript



<script language="javascript" type="text/javascript">



var numericData1 = 522;



var stringData = " JavaScript has strings\n It sure does";



var numericData = 3.14;



var booleanData = true;



document.write("Numeric Data : "+numericData1);



document.write("
String Data : "+stringData);



document.write("
Floating Data : "+numericData);

Output

In addition, multiple variables can be declared with one var statement, if the variables are separated by commas:

var no1=50, no2=5065;

JavaScript allows the implicit declaration of variables by using them on the left-hand side of an assignment. In JavaScript there is no need to indicate data type during variable 132

Chapter 14 Pages 127-153.indd 132

02/08/18 2:49 PM

www.tn11th.in declarations. JavaScript variables are untyped and it is dynamically datatyped which means initially you can assign a value of any data type to a variable and later you can assign a value of different data type to the same variable. For example:

var value=100;



var value=”JavaScript”;

14.5.5 JavaScript Literals A literal is a fixed value given to a variable in source code. Literals are often used to initialize variables. Values may be Integer, Floating point, Character, String and Boolean. For Example,

var int_const=250; //Integer constant//



var float_const=250.85; //Floating point constant//



var char_const=’A’; //Character constant//



var string_const=”Raman”; //String constant//



var boolean_const=true; //Boolean constant//

write statement: General Syntax:

document write ("string " + var);

14.5.6 Type casting in JavaScript. Type conversion is the act of converting one data type into a different data type which is also called as casting. In JavaScript there are two type of casting, • Implicit casting and • Explicit casting Implicit casting occurs automatically in JavaScript when you change the data stored in a variable:

14.6 JavaScript Operators and Expressions An operator combines the values of its operands in some way and evaluates to a new value. Operators are used for JavaScript’s arithmetic expressions, comparison expressions, logical expressions, assignment expressions. 133

Chapter 14 Pages 127-153.indd 133

02/08/18 2:49 PM

www.tn11th.in An expression is a phrase of JavaScript that a JavaScript interpreter can evaluate to produce a value. The data types are used directly as literals or within variables in combination with simple operators, such as addition, subtraction, and so on, to create an expressions. An expression is a code fragment that can be evaluated to some data type the language s. An expression is simply one or more variables and/or constants ed by operators. An expression is evaluated and produces a result. The result of all expressions may be either an integer or floating-point value or Boolean value. There are three types of expressions as follows, • Arithmetic expressions • Relational expressions • Logical expressions 14.6.1 Arithmetic Operators JavaScript s all the basic arithmetic operators like addition (+), subtraction (–), multiplication (*), division (/), and modulus (%, also known as the remainder operator). Table: 14.1 – Arithmetic Operators Arithmetic Operator + -

Meaning

Example

Result

Addition Subtraction

var sum = 20 + 120 var diff = 20 – 120

Variable sum = 140 Variable diff = 100

*

Multiplication

var prod = 10 * 100

Variable prod = 1000

/

Division

var res = 100/522

%

Modulus operator var rem = 100 % 522

Variable res = 5.22 Variable rem = 22 (remainder)

Illustration 14.3 Using Arithmetic Operators <Title>Demo Program – To test Arithmetic Operators in JavaScript

<script language="javascript" type="text/javascript">

134

Chapter 14 Pages 127-153.indd 134

02/08/18 2:49 PM

www.tn11th.in



var value1 = 522, value2=10;



document.write("
Data1 : "+value1);



document.write("
Data2 : "+value2);



var sum = value1+value2;



var diff = value1-value2;



var prod = value1*value2;



var res = value1/value2;



var rem = value1%value2;



document.write("

The Sum of Data1 and Data2 : "+sum);



document.write("
The Difference of Data1 and Data2 : "+diff);



document.write("
The Product of Data1 and Data2 : "+prod);



document.write("
The Result after Division of Data1 and Data2 : "+res);

document.write("
The Remainder after Division of Data1 and Data2 : "+rem); Output:

14.6.2 Assignment Operator An assignment operator is the operator used to assign a new value to a variable. Assignment operator can also be used for logical operations such as bitwise logical operations or operations on integral operands and Boolean operands. 135

Chapter 14 Pages 127-153.indd 135

02/08/18 2:49 PM

www.tn11th.in In JavaScript = is an assignment operator, which is used to assign a value to a variable. Often this operator is used to set a variable to a literal value, for example,

var number1=10;



var number2=number1;



var name=”Computer Science”;



var booleanvar=true;

The assignment operator is used to assign a value to a single variable, but it is possible to perform multiple assignments at once by stringing them together with the = operator. For example, the statement

var m = n = z = 25; // sets all three variables to a value of 25//

The assignment operator can also be used to set a variable to hold the value of an expression. For example,

var x = 102 + 5 - 50; // x set to 57 //

JavaScript s some shorthand arithmetic operators like +=, -=, *=, /= and %= to evaluate arithmetic calculations. Table: 14.2 Shorthand Arithmetic operators Shorthand Arithmetic Operator

Meaning

+=

Add and assign

-=

Subtract and assign

*=

Multiply and assign

/=

Division

%=

Modulus operator

Example var sum = 120; sum += 20; var diff = 120; diff –= 20; var prod = 100; prod *=10; Var res = 522; Res/=100 Var rem = 522; rem %= 100

Result Variable sum = 140 Variable diff = 100 Variable prod = 1000 Variable res = 5.22 Variable rem = 22 (remainder)

136

Chapter 14 Pages 127-153.indd 136

02/08/18 2:49 PM

www.tn11th.in

Illustration 14.4 Using Arithmetic Shorthand Operators <Title>Demo Program - To test Arithmetic Shorthand Operators in JavaScript <Title>Demo Program - To test Arithmetic Shorthand Operators in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2=10; document.write("
Data1 : "+value1); document.write("
Data2 : "+value2); var sum = value1; sum+=value2; var diff = value1; diff-=value2; var prod = value1; prod*=value2; var res = value1; res/=value2; var rem = value1; rem%=value2; document.write("

The Sum of Data1 and Data2 Using += : "+sum); document.write("
The Difference of Data1 and Data2 Using -= : "+diff); document.write("
The Product of Data1 and Data2 Using *= : "+prod); document.write("
The Result after Division of Data1 and Data2 using /= : "+res); document.write("
The Remainder after Division of Data1 and Data2 Using %= : "+rem);

137

Chapter 14 Pages 127-153.indd 137

02/08/18 2:49 PM

www.tn11th.in Output:

Assignment: Develop JavaScript code for the following: 1. To find Simple Interest for the given Principle, Number of years and Rate of interest. 2. To find Compund Interest for the given Principle, Number of years and Rate of interest. 3. To find difference between Simple Interest and Compound Interst. 14.6.3 Relational or Comparison Operators: Relational operators are also called as Comparison operators, they compares two values and the result is true or false. JavaScript provides a rich set of relational operators including == (equal to), != (not equal to), < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to). Using a relational operator in an expression causes the expression to evaluate as true if the condition holds or false if otherwise. Table: 14.3 Relational or Comparison operators Relational (Comparison) Meaning Operator Assume x=10 and y=20 == Equality != In-equality < Less-than > Greater-than <= Less-than or equal to >= Greater-than or equal to

Example

x==y x!=y x y x<=y x>=y

Result

False True True False True False

138

Chapter 14 Pages 127-153.indd 138

02/08/18 2:49 PM

www.tn11th.in Illustration 14.5 Using Relational Operators <Title>Demo Program - To test Relational(Comparison) Operators in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2=10; document.write("
Data1 : "+value1); document.write("
Data2 : "+value2); document.write("

Whether Data1 = Data2 : "+(value1==value2)); document.write("
Whether Data1 < Data2 : "+(value1 Whether Data1 > Data2 : "+(value1>value2)); document.write("
Whether Data1 <= Data2 : "+(value1<=value2)); document.write("
Whether Data1 >= Data2 : "+(value1>=value2)); document.write("
Whether Data1 != Data2 : "+(value1!=value2));

Output:

139

Chapter 14 Pages 127-153.indd 139

02/08/18 2:49 PM

www.tn11th.in 14.6.4 Logical Operators: Logical operators perform logical (boolean) operations. Logical operators combine or invert boolean values. Once comparisons are made, the logical operators && (AND), || (OR) and ! (NOT) can be used to create more complex conditions. Table: 14.4 Logical or Boolean operators Logical Operator &&

Example ((4>5( && )10<5)) ((expr1) && (expr2))

||

((4>5( || )10<5)) ((expr1) || (expr2))

!

!(10<5) !(expr1)

Meaning

Result

(Logical AND) Returns true if True expr1 and expr2 both true. (Logical OR) Returns true if either expr1 or expr2 is true, or both are True true. (Logical NOT) Returns true if expr1 is false; otherwise, returns False false.

Usage : Best practice is to use logical operators on boolean operands. However, operands of any type can be combined. The strict rules are as follows: • For && (AND) the result is false if the first operand is false; otherwise, the result is the Boolean value of the second operand. • For || (OR) the result is true if the first operand is true; otherwise, the result is the Boolean value of the second operand. • For ! (NOT) the result is true if the operand is false; otherwise, the result is true.

140

Chapter 14 Pages 127-153.indd 140

02/08/18 2:49 PM

www.tn11th.in Illustration 14.6 Using Logical Operators <Title>Demo Program - To test Logical Operators in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2=10; document.write("
Data1 : "+value1); document.write("
Data2 : "+value2); var res1=((value1>100) && (value1>601)); var res2=((value1>100) || (value1>601)); var res3=(!(value1!=value2)); document.write("

Whether Data1>100 AND Data1>601 : "+res1); document.write("

Whether Data1>600 OR Data1>601 : "+res2); document.write("
Whether !Data1 != Data2 : "+res3);

Output:

14.6.5 String Operators: One of the built-in features of JavaScript is the ability to concatenate strings. The + operator performs addition on numbers but also serves as the concatenation operator for strings. Because string concatenation has precedence over numeric addition, + will be interpreted as string concatenation if any of the operands are strings. + operator which is also called as the string concatenation operator. For example: 141

Chapter 14 Pages 127-153.indd 141

02/08/18 2:49 PM

www.tn11th.in Illustration 14.7 Using + Operator for concatenating String <Title>Demo Program - To Concatenating (+) Operators in JavaScript <script language="javascript" type="text/javascript"> var String1 = "Java"; var String2 = "Script"; var String3=String1+String2; document.write("
String1 : "+String1); document.write("
String2 : "+String2); document.write("

Concatenated String of String1 and String2 : "+String3);

Output:

14.6.6 Increment and Decrement Operators: The ++ operator increments its single operand. The operator converts its operand to a number, adds 1 to that number, and assigns the incremented value back into the variable. The return value of the ++ operator depends on its position relative to the operand. When ++ is used before the operand, where it is known as the pre-increment operator, it increments the operand and evaluates to the incremented value of that operand. When used after the operand, where it is known as the post-increment operator, it increments its operand but evaluates to the un-incremented value of that operand. Consider the difference between these two lines of 142

Chapter 14 Pages 127-153.indd 142

02/08/18 2:49 PM

www.tn11th.in code:

var m = 1, n = ++m; // m and n are both 2



var m = 1, n = m++; // m is 2, n is 1

The -- operator decrements its single operand. It converts the value of the operand to a number, subtracts 1, and assigns the decremented value back to the operand. Like the ++ operator, the return value of -- depends on its position relative to the operand. When used before the operand, it decrements and returns the decremented value. When used after the operand, it decrements the operand but returns the undecremented value.

var m = 2, n = --m; // m and n are both 1



var m = 2, n = m--; // n is 2, n is 1

143

Chapter 14 Pages 127-153.indd 143

02/08/18 2:49 PM

www.tn11th.in

Illustration 14.8 Using ++ and -- Operator – both Prefix and Suffix <Title>Demo Program - ++ and -- Operators in JavaScript <script language="javascript" type="text/javascript"> var number1 = 150; var number2 = number1++; document.write("

Post Increment - number++

"); document.write("Number1 = "+number1+" Number2 = "+number2); document.write("

Pre Increment - ++number

"); var number1 = 150; var number2 = ++number1; document.write("Number1 = "+number1+" Number2 = "+number2); var number1 = 150; var number2 = number1--; document.write("

Post Decrement - number--

"); document.write("Number1 = "+number1+" Number2 = "+number2); document.write("

Pre Decrement - --number

"); var number1 = 150; var number2 = --number1; document.write("Number1 = "+number1+" Number2 = "+number2);

Output:

144

Chapter 14 Pages 127-153.indd 144

02/08/18 2:49 PM

www.tn11th.in

14.6.7 Unary + and - Operator:

+ has no effect on numbers but causes non-numbers to be converted into

numbers

– Negation (changes the sign of the number or converts the expression to a

number and then changes its sign) 14.6.8 typeof Operator: The typeof operator is used to get the data type (returns a string) of its operand. The operand can be either a literal or a data structure such as a variable, a function, or an object. The operator returns the data type. Syntax

typeof operand

or typeof(operand) typeof returns: boolean, function, number, string, and undefined. The following table summarizes possible values returned by the typeof operator.

145

Chapter 14 Pages 127-153.indd 145

02/08/18 2:49 PM

www.tn11th.in Table: 14.5 Type of Operand

Result

Number

“number”

Boolean

“Boolean”

String

“string”

Functions

“function”

Undefined

“undefined”

Illustration 14.9 typeof operator <Title>Demo Program - To test typeof Operator in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2="JavaSript"; value3=true; document.write("
Value1 ="+value1+" and its data Type is : "+typeof(value1)); document.write ("
Value2 ="+value2+" and its data Type is : "+typeof(value2)); document.write ("
Value3 ="+value3+" and its data Type is : "+typeof(value3));

Output:

14.6.9 Conditional Operator (?:) The ?: is the conditional operator in JavaScript, which requires three operands, hence it is called the ternary operator. The syntax is 146

Chapter 14 Pages 127-153.indd 146

02/08/18 2:49 PM

www.tn11th.in

var variablename=(condition) ? value1 : value2;

In the syntax condition may be relational expression or logical expression. First condition will be evaluated, if the condition returns true then the value of the left side of the colon is assigned to the variable otherwise the value of the right side of the colon will be assigned the variable. For example,

var result=(10>15) ?100 :150;

In the above example, since the condition returns false the value 150 will be assigned to result. Illustration 14.10 Condtional Operator <Title>Demo Program - To test Conditional Operator in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2=150, value3; value3=(value1 The Value of Data1 = "+value3);

Output:

14.7 JavaScript Popup or Dialog Boxes: JavaScript s three important types of dialog boxes. Dialog boxes are also called as Popup Boxes. These dialog boxes can be used to raise an alert, or to get confirmation on any input or to have a kind of input from the s. JavaScript s three kind of popup boxes: Alert box, Confirm box, and Prompt box. 147

Chapter 14 Pages 127-153.indd 147

02/08/18 2:49 PM

www.tn11th.in 14.7.1 Alert Dialog Box: An alert dialog box is mostly used to give a warning message to the s. For example, if one input field requires to enter some text but the does not provide any input, then as a part of validation, you can use an alert box to give a warning message. Alert box gives only one button "OK" to select and proceed.

The syntax of alert box is

Alert(“Message”);

(or) Window.alert(“Message”);

Example:

alert(“Name is compulsory entry”);



(or) window.alert(“Name is compulsory entry”); Illustration 14.11 Alert Dialog Box

<Title>Demo Program - To test Alert Dialog Box in JavaScript



<script language="javascript" type="text/javascript">



var value1 = 522, value2=10;



window.alert("Data1 : "+value1);



alert(“Data1 :”+value2);

Output:

148

Chapter 14 Pages 127-153.indd 148

02/08/18 2:49 PM

www.tn11th.in 14.7.2 Confirm Dialog Box: A confirmation dialog box is mostly used to take 's consent on any option. It displays a dialog box with two buttons: OK and Cancel. If the clicks on the OK button, the confirm() will return true. If the clicks on the Cancel button, then confirm() returns false. The syntax of confirm dialog box is confirm(“message”); (or) window.confirm(“message”); Example: confirm(“Hai Do you want to continue:”); (or) window.confirm(“Hai Do you want to continue:”); Illustration 14.12 Confirm Dialog Box <Title>Demo Program - To test Confirm Dialog Box in JavaScript <script language="javascript" type="text/javascript"> var value1 = 522, value2=10; window.confirm("Data1 : "+value1); confirm("Data2 :"+value2); Output:

149

Chapter 14 Pages 127-153.indd 149

02/08/18 2:50 PM

www.tn11th.in 14.7.3 Prompt Dialog Box: The prompt dialog box is very useful when the want to pop-up a text box to get input. Thus, it enables you to interact with the . The needs to fill in the text box field and then click OK. The prompt dialog box is displayed using a method called prompt() which takes two parameters: (i) a label which you want to display in the text box and (ii) a default string to display in the text box. This dialog box has two buttons: OK and Cancel. If the clicks the OK button, the prompt() will return the entered value from the text box. If the clicks the Cancel button, the prompt() returns null. The Syntax of prompt dialog box is, Prompt(“Message”,”defaultValue”); (or) window.prompt("sometext","defaultText"); Example:

prompt(“Enter Your Name:”,”Name”);

(or)

window.prompt(“Enter Your Name:”,”Name”); Illustration 14.13 Prompt Dialog Box

<Title>Demo Program - To test Prompt Dialog Box in JavaScript



<script language="javascript" type="text/javascript">



var sname = prompt("Please enter your name", "Name");



150

Chapter 14 Pages 127-153.indd 150

02/08/18 2:50 PM

www.tn11th.in Output:

14.8 Comments in JavaScript: Very important aspect of good programming style is to insert remarks and commentary directly in source code, making it more readable to yourself as well as to others. Any comments you include will be ignored by the JavaScript interpreter. There are two types of comments, Single line and Multiple lines comments. Single-line comments begin with a double slash (//), causing the interpreter to ignore everything from that point to the end of the line. Multiple line comments begins with /* and ends with */. For example: // JavaScript single line comment// Multiple line comments begins with /* and ends with */

Points to : • The <script> tag alerts the browser program to start interpreting all the text between these tags as a script • JavaScript is a case sensitive language • The scope of a variable is the life time of a variable of source code in which it is defined • A literal is a fixed value given to a variable in source code. • An expression is a code fragment that can be evaluated to some data type the language s. • Java Script s all basic arithmetic operators like +, - , *, / & % • Java scripts has an in built feature of concatenating strings. • The types of operator is used to get the data type of a variable. • JavaScript s important types of dialog boxes also called as pop up boxes, alert box, confirm dialog box and prompt dialog box. • ?: is the conditional operator in Java Script also called as ternary operator. 151

Chapter 14 Pages 127-153.indd 151

02/08/18 2:50 PM

www.tn11th.in

Evaluation

Choose the correct answer: 1.

Part-I



Which provided a common scripting language to web developers to design, test and deploy Internet Application A) C B) C++ C) Java D) JavaScript

2.

Expand CGI



A) Common Gateway Interface

B) Complex Gateway Information



C) Common Gateway Information

D) Complex Gateway Interface

3.

JavaScript programming language is used to develop the



A) Dynamic Web Page

4.

The Dynamic Web Page help to save server’s



A) Work

5.

entered data, is validated before sending it to server is called



A) Server traffic

B) Dynamic Web Page



C) Server Route

D) Web server

6.

Java Scripts can be implemented using which statements?



A)

B) Window B) Route

B) <Java>

C) Web Page

D) Home Page

C) Traffic

D) Pvath

C) <script>

D)

7. Expand

A) Distance Hyper Text Markup language

B) Dynamic Hyper Text Markup language



C) Distance High Text Markup language

D) Dynamic High Text Markup language

8.

How many attributes specifies that <script> tag in the scripting

A) 2 B) 3 C) 4 D) 5 9.

Which attribute is used to indicate the scripting language and its value should be sent to “ Text/JavaScript”



A) Language

B) Text1

C) Type

D) Body

10. The file reload into the browser use the shortcut key is A) F2 B) F3 C) F4 D) F5 11. JavaScript ignores spaces that appear between

A) Command

B) Scripts

C) Tokens

D) Text

12. A Data value for variable that appears directly in a program by using a

A) loop

B) Literal

C) Statement

D) Text

152

Chapter 14 Pages 127-153.indd 152

02/08/18 2:50 PM

www.tn11th.in 13. Which is mostly used to give a warning message to s?

A) Alert Dialog Box

B) Confirm box



C) Prompt box

D) Display box

14. In the below snippet, value of x is var x = 250 + 2 – 200; A) 50 B) 52 C) 48 D) 42 Part-II Answer to the following questions (2 Marks): 1. 2. 3. 4. 5. 6. 7. 8. 9.

Write a syntax of <script> tag What is scope of variables and types of scope variable? Write a notes to type casting in JavaScript How many Literals in JavaScript and mention its types. What is conditional operator give suitable example. What are the comments in Java Script? Write note on types of Operator. Write the role of variable in JavaScript. What is the uses of prompt dialog box? Part-III

Answer to the following question (3 Marks):: 1. 2. 3. 4. 5. 6.

What are the advantages of programming language? Brief the basic data types in Java Scripts. Write note on string Operator. Write about <script> tag What are the uses of Logical Operators? Difference between the increment and Decrement operator. Part –IV

Answer to the following questions (5 Marks): 1.

Explain about the popup dialog boxes in JavaScript.

2.

Explain about the Arithmetic operator with suitable example.

Case study: Develop a program for online registration form with some of the client side validation features Reference : 1. Title - Pure JavaScript Author : R.Allen Wyke, Jason D. Gilliam and Charlton Ting, Publisher : Techmedia 2. Computer Application Text Book – Govt. of Kerala 153

Chapter 14 Pages 127-153.indd 153

02/08/18 2:50 PM

www.tn11th.in

Unit IV

JavaScript

CHAPTER

15

Control Structure in JavaScript Learning Objectives: • To learn about control structures • To learn about logical operators in JavaScript • To learn about loops and their types • To acquire knowledge of developing JavaScript programs.

15.1 Conditional Statements in JavaScript: Statements are executed in the order they are found in a script. Conditional statements execute or skip one or set of statements depending on the value of a specified conditional expression. There are two types of controls, • Branching / Selection • Looping / repetitive 15.1.1 Branching Statements: JavaScript s branching statements which are used to perform different actions based on different conditions. Branching is a transfer of control from the current statement to another statement or construct in the program unit. A branch alters the execution sequence. There are different branching statements. They are,

• if statement



• if … else statement



• else if statement



• switch statement

15.1.1.1 if and if..else Statement: The if statement is the fundamental control statement that allows JavaScript to make decisions to execute statements conditionally. This statement has two forms. The form is for only true condition. The syntax is 154

Chapter 15 Pages 154-175.indd 154

02/08/18 2:53 PM

www.tn11th.in



if (condition)

{ True block; } In the if form, condition contains relational/logical expression is evaluated. If the resulting value is true the true block is executed. True block may contain one or more than one statement. For example Illustration 15.1 Demo to Test if command

<Title>Demo Program - To test if command in JavaScript



<script language="javascript" type="text/javascript">



var age = prompt("Please enter your Age :", "0");

if(age>=16) {

alert("You Are Eligible to Vote ....");

} The output will be Demo Program - To test

← →

X

-

X

file:///C:/s/ELCOT/Desktop/SCERT/Fin...

X . . .

This page says Please enter your Age: 35 OK

Cancel

155

Chapter 15 Pages 154-175.indd 155

02/08/18 2:53 PM

www.tn11th.in

Demo Program - To test

← →

X

-

X

file:///C:/s/ELCOT/Desktop/SCERT/Fin...

X . . .

This page says You Are Eligible to Vote.... OK

The second form of the if statement is an else clause that is the program to follow either of two branches depending on the condition. In the simple if construction, no special processing is performed when the condition evaluates to false. But if processing must follow one of two paths, hence need to use if...else format. Its syntax is:

if (expression)

{

statements if true

} else { statements if false } This form is similar to if statement but the only difference is the else keyword, which provides an alternate path for execution to follow if the condition evaluates to false. Illustration 15.2 Using if.. else statement <Title>Demo Program - To test if..else command in JavaScript <script language="javascript" type="text/javascript"> var age = prompt("Please enter your Age :", "0");

156

Chapter 15 Pages 154-175.indd 156

02/08/18 2:53 PM

www.tn11th.in

if(age>=18) { alert("You Are Eligible to get Driving Licence.."); } else { alert("You Are Not Eligible to get Driving Licence.."); } The output will be ←

→

C:\\ELCOT\Desktop\SCER ^

X

-

^

Search...

X

Demo Program - To test if c... X

X

Explorer Prompt Script Prompt: Please enter you Age:

OK Cancel

35

X

Message from webpage

! You Are Eligible to get Driving Licence..

OK

157

Chapter 15 Pages 154-175.indd 157

02/08/18 2:53 PM

www.tn11th.in

Explorer Prompt

X

OK

Script Prompt:

Cancel

Please enter your Age: 15

X

Message from webpage

! You Are Not Eligible to get Driving Licence..

OK

15.1.1.2 else if Statement: The if ... else statement evaluates an expression and executes one of two pieces of code, depending on the outcome. The else if statement to specify a new condition if the first condition is false. if (n == 10) { // Execute code block #1 } else if (n == 20) { // Execute code block #2 } else if (n == 30) { // Execute code block #3 } else { // If all else fails, execute block #4 } 158

Chapter 15 Pages 154-175.indd 158

02/08/18 2:53 PM

www.tn11th.in

Illustration 15.3 Using Logical Operators and else if Statement



<Title>Program - To test else ..if command in JavaScript



<script language="javascript" type="text/javascript">



var marks = prompt("Please enter your Marks/100 :", "0");

if(marks>90) {

document.write("Your Grade is Outstanding..");

}

else if((marks>70) && (marks<=90))

{

document.write("Your Grade is Excellent..");

}

else if((marks>50) && (marks<=70))

{

document.write("Your Grade is Good..");

}

else if((marks>40) && (marks<=50))

{

document.write("Your Grade is Satisfectory..");

} else {

document.write("Your Grade Poor and have to re-appear Exam..");

}

159

Chapter 15 Pages 154-175.indd 159

02/08/18 2:53 PM

www.tn11th.in The output will be

There is nothing special about this code. It is just a series of if statements, where each following if is a part of the else clause of the previous statement. Using the else if idiom is preferable to, and more legible than, writing these statements out in their syntactically equivalent, fully nested form:

if (n == 10)

{ 160

Chapter 15 Pages 154-175.indd 160

02/08/18 2:53 PM

www.tn11th.in

// Execute code block #1

} else {

if (n == 20)

{

// Execute code block #2

} else {

if (n == 30)

{

// Execute code block #3

} else

{



// If all else fails, execute block #4

} } } 15.1.1.3 switch case Statement: JavaScripts offers the switch statement as an alternate to using if...else structure. The switch statement is especially useful when testing all the possible results of an expression. The syntax of a switch structure as the following:

161

Chapter 15 Pages 154-175.indd 161

02/08/18 2:53 PM

www.tn11th.in switch(expression) { `

case label1:

statements1; break;

case label2:

statements2; break;

case labeln;



statements - N;

break; default: statements; } 15.1.1.4 Break and Default Statement The switch statement begins by evaluating an expression placed between parenthesis, much like the if statement. The result compared to labels associated with case structure that follow the switch statement. If the result is equal to a label, the statements in the corresponding case structure are executed. The default structure is can be at the end of a switch structure if the result of the expression that do not match any of the case labels. The break statement is also used commonly within switch to exit the statement once the appropriate choice is found.

162

Chapter 15 Pages 154-175.indd 162

02/08/18 2:53 PM

www.tn11th.in

Illustration 15.4 Using Switch Statement <Title>Program - To test witch command in JavaScript <script language="javascript" type="text/javascript"> var grade=0; var marks=prompt(“Please enter your marks/100:”,”0”); if(marks>90) {grade=1;} else if(marks>70)&&(marks<=90) {grade=2;} else if(marks>50)&&(marks<=70) {grade=3;} else if(marks>40)&&(marks<=50) {grade=4;} else {grade=5;} switch(grade) { case 1: document.write("Your Grade is Outstanding.."); break; case 2: document.write("Your Grade is Excellent.."); break; case 3: document.write("Your Grade is Good.."); break; case 4: document.write("Your Grade is Satisfectory.."); break; default: document.write("Your Grade Poor and have to re-appear Exam.."); } 163

Chapter 15 Pages 154-175.indd 163

02/08/18 2:53 PM

www.tn11th.in The output will be -

X Search... Demo Program - To test else c...i.. Program - To test witch co... X C:\\ELCOT\Desktop\SCER ^

^

X

X

Explorer Prompt Script Prompt: Please enter your Marks/100:

OK Cancel

98

-

^ X Search... Demo Program - To test else c...i.. Program - To test witch co... X C:\\ELCOT\Desktop\SCER ^

X

Your Grade is Outstanding...

164

Chapter 15 Pages 154-175.indd 164

02/08/18 2:53 PM

www.tn11th.in 15.2 Looping / repetitive In JavaScript there are times when the same portion of code needs to be executed many times with slightly different values is called Loops. JavaScript s three kinds of looping statements. They are





• for loop



• while loop



• do..while loop

15.2.1 for loop The for loop is a very rigid structure that loops for a pre-set number of times. In JavaScript for structure is very flexible, which makes this type is very useful. The syntax of the for loop looks like the following:

for(initialization; condition; increment/decrement)

{ Body of the loop; } The for structure within parenthesis there are three parts each separated by semicolon. They are, 1. The first part of the loop initialize a variable which is also called as control variable. In most case the control variable is declared as well as initialized. 2. The second part is the conditional statement that determines how many times the loop will be iterated. 3. The third and final part determines how the value of control variable is changed (Incremented/Decremented)

165

Chapter 15 Pages 154-175.indd 165

02/08/18 2:53 PM

www.tn11th.in

Illustration 15.5 Using for loop <Title> Program - To test for statement in JavaScript <script language="javascript" type="text/javascript"> var no1 = prompt("Please enter Table You want :", "0"); document.write("

Multiplication for your need

"); for( var no2=0;no2<=10;no2++) { document.write(no1+" x "+no2+" = "+no1*no2+"
"); }

166

Chapter 15 Pages 154-175.indd 166

02/08/18 2:53 PM

www.tn11th.in

-

X

C:\\ELCOT\Desktop\SCER ^ Search...

Demo Program - To test Pr.. Multiplication for your need 3x3=0 3x1=3 3x2=6 3x3=9 3 x 4 = 12 3 x 5 = 15 3 x 6 = 18 3 x 7 = 21 3 x 8 = 24 3 x 9 = 27 3 x 10 = 30

15.2.2 break and continue statement JavaScript also s statements used to modify flow control, specifically break and continue. The break statement will terminate the loop early. For example,

for(var n=0;n<=10;n++)

{ if(n==5) { break; } document.write(n+"
"); } In the above example, which writes out the value of n starting from 0, when n is equal to 5 the break statement is executed and the loop is terminated and the output is as follows, 167

Chapter 15 Pages 154-175.indd 167

02/08/18 2:53 PM

www.tn11th.in

Illustration 15.6 Using break statement <Title>Demo Program - To test Break command in JavaScript <script language="javascript" type="text/javascript">

document.write("

Using Break Statement

"); for( var no2=0;no2<=10;no2++) { if(no2==5) {break;} document.write(no2+" "); }



-

X

C:\\ELCOT\Desktop\SCER ^ Search...

Demo Program - To test Pr.. Using Break Statement 01234

The continue statement will skip back to the loop condition check. When the continue statement is executed, the current iteration of the enclosing loop is terminated, and the next iteration begins. For example, 168

Chapter 15 Pages 154-175.indd 168

02/08/18 2:53 PM

www.tn11th.in

for(var n=0;n<=10;n++)

{ if(n==5) { continue; } document.write(n+"
"); } In the above example, which writes out the value of n starting from 0, when n is equal to 5 the continue statement is executed and the continue statement continues the loop without printing the value 5 and the output is as follows, Illustration 15.7 Using continue statement <Title>Demo Program - To test Continue command in JavaScript <script language="javascript" type="text/javascript"> document.write("

Using continue Statement

"); for( var no2=0;no2<=10;no2++) { if(no2==5) {continue;} document.write(no2+" "); }



169

Chapter 15 Pages 154-175.indd 169

02/08/18 2:53 PM

www.tn11th.in

-

X

C:\\ELCOT\Desktop\SCER ^ Search...

Demo Program - To test Pr.. Using Continue Statement 0 1 2 3 4 6 7 8 9 10

15.2.3 while loop In JavaScript while loop is another most basic loop. The purpose of a while loop is to execute a statement /block of statement repeatedly as long as an expression is true. The while statement creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated before executing the statement. The syntax is:

while (condition)

{

body of the loop

} Illustration 15.8 Using while loop <Title>Program - To test while statement in JavaScript <script language="javascript" type="text/javascript"> document.write("

Using while Statement

"); var no2=0; while(no2<=5) { document.write(no2+" "); no2=no2+1; } 170

Chapter 15 Pages 154-175.indd 170

02/08/18 2:53 PM

www.tn11th.in

-

X

C:\\ELCOT\Desktop\SCER ^ Search...

Demo Program - To test Pr.. Using While Statement 01234

To execute a while statement, the interpreter first evaluates expression. If the value of the expression is true the interpreter executes the statement and repeats, jumping back to the top of the loop and evaluating expression again. In the above example let us see how the while command is executed, 1. Initial value of the variable no2 is set to 0 2. The expression in the while statement is executed 3. If the condition is true then body of the loop will be executed once otherwise body of the loop will be skipped and control will jump to next statement to end of the loop. 4. Then the value of the control variable is executed and control jumps to condition again go to step 3 15.2.4 do .. while loop The do..while loop is like a while loop, except that the loop expression is tested at the end of the loop rather than at the beginning. This means that the body of the loop is always executed at least once. The syntax is:

do

{

body of the loop

} while (expression);

An important difference between while and do..while statement is in the do..while loop body of the loop always executed at least once before the condition can be executed. In a while 171

Chapter 15 Pages 154-175.indd 171

02/08/18 2:53 PM

www.tn11th.in loop, first condition will be evaluated and then only based on the result of the condition the body of the loop will be executed or not. Illustration 15.9 Using do..while loop <Title>Program - To test do..while statement in JavaScript <script language="javascript" type="text/javascript"> document.write("

Using do..while Statement

"); var no2=0; do { document.write(no2+" "); no2=no2+2; }while(no2<=10);

Output: -

X

C:\\ELCOT\Desktop\SCER ^ Search...

Demo Program - To test Pr.. Using do..while Statement 0 2 4 6 8 10

Exercise Write a JavaScript Program for the following: a) To display Odd number from 1 to N numbers. b) To display any Multiplication table as the required. c) To display as 10,9,8,……0 172

Chapter 15 Pages 154-175.indd 172

02/08/18 2:53 PM

www.tn11th.in

Points to : • Conditional Statements help to alter the normal sequence of execution of a program by two types of controls - Branching and Looping. • The three logical operators in Jave Script are &&, !! & !. • The break statement is commonly used to exit the statement once the appropriate choice is found. • The for is a very rigid, flexible structure that loops for a pre set number of times. • The break statement terminates the loop irrespective of the condition and the continue statement executes the next iteration of the loop.

Evaluation Part - I Choose the correct answers: 1. Which conditional statement is used to transfer control from current statement to another statement? (LOT) (a) Branching (b) Sequencing (c) Looping (d) Interating 2.

_______ statement can be used as alterative to if-else statement. (LOT) (a) While (b) If (c) Else-if (d) Switch

3.

Which statement in switch case is used to exit the statement once the appropriate choice is found? (MOT) (a) Exit (b) Default (c) Case (d) Break

4.

Which of the following is not a looping statement? (LOT) (a) Switch (b) While (c) Do-While (d) For

5.

Which part of the loop statement determines the number of times, the loop will be iterated? (MOT) (a) First (b) Second (c) Third (d) Final

6.

Which of the following is not a branching statement? (LOT) (a) Loop (b) If-else (c) Switch (d) For

7. What will be the output for the following snippet: For (var n=0; n<10; n+1) { if (n==3) { break; } 173

Chapter 15 Pages 154-175.indd 173

(HOT)

02/08/18 2:53 PM

www.tn11th.in document write (n+"
"); } (a) 0 1 2 (b) 0 1 2 3

(c) 0 1 2 3 4

(d) 0, 1, 3

8.

In which loop the condition is evaluated, before executing a statement?



(a) While

9.

The _______ statement is especially useful when testing all the possible results of an expression. (LOT)



(a) While

(b) Do while

(c) Break

(b) Do while

(c) Switch

(MOT)

(d) Continue

(d) If

10. In the _____ loop, body of the loop always executed at least once before the condition can be executed. (LOT)

(a) For

(b) While

(c) If

(d) Do while

11. <script type = "text / javascript">

x = 6 + "3";



document write (x);



<'script> what will be the output?



(a) 6

(b) 9

(c) 63

(d) Error Part - II

Answer to the following questions (2 Marks): 1.

What are the different types of control statement used in JavaScript?

2.

What is meant by conditional statements in JavaScript?

3.

List out the various branching statements in JavaScript?

4.

Write the general syntax for switch statement

5.

Differentiate the break and continue statement. Part - III

Answer to the following questions (3 Marks): 1. What if if statement and write its types. 2.

Write the syntax for else-if statement.

3.

What is called a loop and what are its types?

4.

Differentiate between while and do while statements

174

Chapter 15 Pages 154-175.indd 174

02/08/18 2:53 PM

www.tn11th.in 5.

What message will be displayed, if the input for age is given as 20, for the following snippet.



if (age> = 18 )

{

alert ("you are eligible to get Driving licence"}

} else

alert ("you are not eligible to get driving licence");

} Part - IV

Answer to the following questions (5 Marks): 1.

Explain for loop with example

2.

Explain switch case statement with example

3.

Write the output for the following program



<Title> for statement



<script language= "java Script" type = "text / javaScript")



var no1= prompt ("please enter table you want:", "0" );



document write ("

multiplication for your need

")



for (Var no2= 0; no2<=10; no2++)

{

document write (no1+ "x" + no2+ "=" + no1+no2+ "
);

} 4.

Write a Java Script program using while statement to display 10 numbers.

175

Chapter 15 Pages 154-175.indd 175

02/08/18 2:53 PM

www.tn11th.in

Unit IV

JavaScript

CHAPTER

16

JavaScript Functions Learning Outcomes The students will learn the following: • How to implement the function in JavaScript • How to use Pre-defined functions • How to create and use -defined functions • To create an Online application

16.1 Introduction A function is a block of JavaScript code that is defined once but may be executed or invoked any number of times. Functions are used to encapsulate code that performs a specific task. Sometimes functions are defined for commonly required tasks to avoid the repetition entailed in typing the same statements over and over. More generally, they are used to keep code that performs a particular job in one place in order to enhance reusability and program clarity. JavaScript functions are parameterized or non-parameterized. A parameterized function definition may include a list of identifiers, known as parameters that work as local variables for the body of the function. Function invocations provide values or arguments for the function’s parameters. Functions often use their argument values to compute a return value that becomes the value of the function invocation expression.

JavaScript s two types functions. They are

• Pre-defined or Library Functions • -defined Functions 16.2 Some common pre-defined functions. Pre-defined functions are already defined in the JavaScript library which are also called Library functions. For example isNaN(), toUpperCase(), toLowerCase(), length(), alert(), prompt(),write() etc., are pre-defined functions. 176

Chapter 16 Pages 176-183.indd 176

02/08/18 2:53 PM

www.tn11th.in Table: 16.1 Predefined functions Function toUpperCase() toLowerCase() length parseInt() parseFloat()

Description Used to convert given string into uppercase Used to convert given string into lowercase Used to find length of the given string Used to convert the given float value into an integer Used to convert the given string into a integer

Example x=”java” x.toUpperCase();

Result

x=”JAVA” x.toLowerCase();

java

x=”JAVA” x.length(); parseInt(34.234);

4

parseInt(“34.23”);

34.23

JAVA

34

16.3 defined functions -defined functions allow the programmer to modularize a program. Most computer programs that solve real-world problems are much large, occupy more space in the computer memory and takes more time to execute. Hence such large programs are divided into small programs are called modules. Function Definition The format of a function definition is



Function function-name(parameters list)

{

{

Declaration of variable Executable statements;

}

{





Function Body

Note: • The function-name is any valid identifier.

For Example: sum

• The parameter list contains one or more valid variable name. • Parameter list contains more than one variable then comma must be there between the 177

Chapter 16 Pages 176-183.indd 177

02/08/18 2:53 PM

www.tn11th.in variable. For example: function sum(x,y) • The function body must be enclosed by braces. Example: function sum(x,y) { var m=x+y; return m; } Listing 16.1 Using Function <script type="text/JavaScript">

Example for Function

"); document.writeln("First No :" + v1 + "
Second No :" + v2 + "
The Sum = " + s); function sum(x, y) { var s=x+y; return s; } //--> 178

Chapter 16 Pages 176-183.indd 178

02/08/18 2:53 PM

www.tn11th.in Output:

The isNaN() function is used to check whether the given value or variable is valid number. This function returns true if the given value is not a number. For example isNaN(“12”), isNaN(“A”). Listing 16.2 Using isNaN() Function

Example Program to test isNan() Function

<script language="JavaScript"> function checknum() { var n=document.form1.text1.value; if(isNaN(n)==true) { document.form1.text2.value="Not a Number : "+n;

179

Chapter 16 Pages 176-183.indd 179

02/08/18 2:53 PM

www.tn11th.in

} else { document.form1.text2.value="It is Number : "+n; } } Enter a Number1:


Output:

180

Chapter 16 Pages 176-183.indd 180

02/08/18 2:53 PM

www.tn11th.in

Listing 16.3 Using Function (on-line quiz) <script type="text/JavaScript"> function checkAnswer() { //var myQuiz=document.getElementById("myQuiz"); if ( document.getElementById("myQuiz").elements[0].checked) alert("Congratulations, Your Answer is correct"); else alert("Your Answer is incorrect, Please try Again"); }

Which is not a Programming Language:
MS-Word COBOL C++ Visual BASIC

Output:

181

Chapter 16 Pages 176-183.indd 181

02/08/18 2:53 PM

www.tn11th.in

Note: • The getElementById() method returns the element that has the ID attribute with the specified value. (In this example, ID is received from form tag). • elements[0] indicates the first option given in the question (Ms-word) Points to : • A function is a block of JavaScript code that is defined once but can be invoked for any number of times. • There are 2 types of functions predefined and defined functions • Predefined functions are also called Library function • defined functions allow the programmer to modularize a program • Larger programs divided into smaller are called modules.

182

Chapter 16 Pages 176-183.indd 182

02/08/18 2:53 PM

www.tn11th.in

Evaluation Part-I Choose the correct answer: 1. The parameters work as A) Local variable C) File variable

B) Global Variable D) block variable

2. Predefined functions are also called as A)Library functions C) instructions

B) storage functions D) commands

3. Larger programs are divided into smaller are called

A) modules

B) block



C) sets

D) Group

4. Which of the following is used to enhance reusability and program clarity. A) functions B) modules C) sets D) instructions 5. Which of the following allow the programmer to modu/arize a program A) Library functions B) defined functions C) Normal functions D) Ordinary functions Part-II Answer to the following questions (2 Marks): 1. 2. 3. 4. 5.

What is a function in JavaScript? What is the use of function? Write a note on Library functions. Write a note on defined functions. Write the syntax of functions.

Part III Answer to the following questions (3 Marks): 1. Write a program in JavaScript to find the cube of a number using function 2. Write a program in JavaScript to find the sum of 10 numbers using function. Case study Display a menu as web page, Accept the choice as input and display the result using function. The menu to be displayed is 1. Sum of numbers upto a given limit 2. Sum of numbers from a starting limit to ending limit. 183

Chapter 16 Pages 176-183.indd 183

02/08/18 2:53 PM

www.tn11th.in

Unit V

COMPUTER ETHICS AND CYBER SECURITY

CHAPTER

17

COMPUTER ETHICS AND CYBER SECURITY Learning Outcomes • To know about cyber-crimes. • To understand the guidelines and need for ethics in cyber-world. • To understand issues related to cyber-crimes. • To know the functionality of firewalls and proxy servers. • To learn aboutencryption and decryption. • To gain knowledge on the IT Act.

17.1 INTRODUCTION Internet is a communication media which is easily accessible and open to all. Information Technology iswidespread through computers, mobile phones and internet. There is a lot of scope and possibility for misuse of Information Technology. Computer systems in general are vulnerable. They play an important role in the daily lives of individuals and businesses. Special care must be taken explicitly in order to ensure that the valuable data do not get into wrong hands. Hence, the data need to be protected. A cyber-crime is a crime which involves computer and network.This is becoming a growing threat to society and is caused by criminals or irresponsible action of individuals who are exploiting the widespread use of Internet. It presents a major challenge to the ethical use of information technologies. Cyber-crime also poses threats to the integrity, safety and survival of most business systems. Figure. 17.1 presents the types of cyber-crimes that happen across the world.

184

Chapter 17 Pages 184-199.indd 184

02/08/18 2:56 PM

www.tn11th.in

PHISHING

VIRUSES

HACKING CYBER CRIMES

PIRACY

IDENTITY THEFTS PHARMING

ONLINE FINANCIAL TRANSACTIONS

Figure 17.1 Types of cyber – crimes ETHICS

been proven to be a boon to individuals as well as various organizations and businesses. e-Commerce is becoming very popular among businesses as it helps them to reach a wide range of customers faster than any other means.

Ethics means “What is wrong andWhat is Right”. It is a set of moral principles that rule the behavior of individuals who use computers. An individual gains knowledge to follow the right behavior, using morals that are also known as ethics. Morals refer to the generally accepted standards of right and wrong in the society. Similarly, in cyberworld, there are certain standards such as

• Do not use unauthorized s

Computer ethics deals with the procedures, values and practices that govern the process of consuming computer technology and its related disciplines without damaging or violating the moral values and beliefs of any individual, organization or entity.

• Do not steal others’ s

GUIDELINES OF ETHICS

• Do not hack

Generally, the following guidelines should be observed by computer s:

• Do not use pirated software

The core issues in computer ethics are based on the scenarios arising from the use of internet such as privacy, publication of copyrighted content, unauthorized distribution of digital content and interaction with web sites, software and related services.

1. Honesty:s should be truthful while using the internet. 2. Confidentiality: sshould not share any important information with unauthorized people.

COMPUTER ETHICS

3. Respect: Each should respect the privacy of other s.

With the help of internet, world has now become a global village. Internet has 185

Chapter 17 Pages 184-199.indd 185

02/08/18 2:56 PM

www.tn11th.in 4. Professionalism: Each should maintain professional conduct. 5. Obey The Law: s should strictly obey the cyber law in computer usage. 6. Responsibility: Each should take ownership and responsibility for their actions Ethics is a set of moral principles that govern the behavior of an individual in a society, and Computer ethics is set of moral principles that regulate the use of computers by s.

17.2 ETHICAL ISSUES An Ethical issue is a problem or issue that requires a person or organization to choose between alternatives that must be evaluated as right (ethical) or wrong (unethical). These issues must be addressed and resolved to have a positive influence in society. Some of the common ethical issues are listed below: • Cyber crime • Software Piracy • Unauthorized Access • Hacking • Use of computers to commit fraud • Sabotage in the form of viruses • Making false claims using computers CYBER CRIME Cybercrime is an intellectual, white-collar crime. Those who commit such crimes generallymanipulate the computer system in an intelligent manner. For example – illegal money transferviainternet. Examples of some Computer crimes and their functions are listed below in Table 17.1:

186

Chapter 17 Pages 184-199.indd 186

02/08/18 2:56 PM

www.tn11th.in Table 17.1 Crime

Function Hacking, threats, and blackmailing towards a Crime Function business or a person. Cyber stalking Harassing through online. Malicious programs that can perform a variety of functions including stealing, encrypting or deleting Malware sensitive data, altering or hijacking core computing functions and monitoring ’s computer activity without their permission. Overloading a system with fake requests so that it Denial of service attack cannot serve normal legitimate requests. Manipulating data, for example changing the banking Fraud records to transfer money to an unauthorized . A person or program collects and Harvesting information from a legitimate to illegally gainaccess to others’ (s). It is a crime where the criminals impersonate Identity theft individuals, usually for financial gain. Stealing practical or conceptual information Intellectual property theft developed by another person or company. Salami slicing Stealing tiny amounts of money from each transaction. Tricking people into believing something that isnot Scam true. Distribute unwanted e-mail to a large number Spam ofinternet s. It is a malicious practice in which communication Spoofing is send from unknown source disguised as a source known to the receiver. SOFTWARE PIRACY

this data either for one’s own benefit or for commercial profit.

Software Piracy is about the copyright violation of software created originally by an individual or an institution. It includes stealing of codes / programs and other information illegally and creating duplicate copies by unauthorized means and utilizing

In simple words,Software Piracy is “unauthorized copying of software”.Figure 17. 3 shows a diagrammatical representation of software piracy.

187

Chapter 17 Pages 184-199.indd 187

02/08/18 2:56 PM

www.tn11th.in are made available to the public illegally are often called warez.

SOFTWARE PIRACY

UNAUTHORIZED ACCESS

Duplicating and selling copyrighted programs

Unauthorized access is when someone gains access to a website, program, server, service, or other system by breaking into a legitimate . For example, if someone tries guessing a or name for an that was not theirs until they gained access, it is considered an unauthorized access.

ing software illegally through network

Figure 17.2- Diagrammatic representation of Software piracy

To prevent unauthorized access, Firewalls, Intrusion Detection Systems (IDS), Virus and Content Scanners, Patches andHot fixes are used.

Most of the commercial software is licensed for use at a single computer site or for use by only one at any time. When a buysany software, he becomes a licensed for that software. He is allowed to make copies of the program for backup purposes, but it is against the law to distributeduplicate copies to others. Such illegal copying and distribution of commercial software should not be practiced.

HACKING Hacking is intruding into a computer system to steal personal data without the owner’spermission or knowledge (liketo steal a ). It is also gaining unauthorized access to a computer system, and altering its contents. It may be done in pursuit of a criminal activity or it may be a hobby. Hacking may be harmless if the hacker is only enjoying the challenge of breaking systems’ defenses, but such ethical hacking should be practiced only as controlled experiments. Figure 17.4 shows a diagrammatic representation of Hacking.

An entirely different approach to software piracy is called shareware, acknowledges the futility of trying to stop people from copying software and instead relies on people’s honesty. Shareware publishers encourage s to give copies of programs to friends and colleagues but ask everyone who uses that program regularly to pay a registration fee to the program’s author directly. Commercial programs that

188

Chapter 17 Pages 184-199.indd 188

02/08/18 2:56 PM

www.tn11th.in cracking can be performeither by using an automatedprogram or can be manually realized.

The act of gaining illegal access to a computer

One more interesting fact about cracking is social engineering. It is a method of getting s and information using human weakness. These crackers trick people, not software. They can use just the phone for getting information, they can pretend being your friend and talk to you on Internet Relay Chat(IRC) or by Instant messenger. e-mail can also be a source for them. They may send official e-mail requesting some sensitive information. It may look like a legitimate e-mail from bank or other official institution.

HACKING

Leads to

Identity theft or gaining personal information

Protected by

Firewalls, s and Id’s , anti hacking software

Figure 17.3 Diagramatic representation of Hacking

The other method that uses social engineering crackers is guessing. They find your personal information from some personal data/facts and try to guess a .

CRACKING Cracking is where someone edits a program source so that the code can be exploited or modified. A cracker (also called a black hat or dark side hacker) is a malicious or criminal hacker. “Cracking” means trying to get into computer systems in order to steal, corrupt, or illegitimately view data.

Usually a cracker maintains knowledge of the vulnerabilities he or she finds and exploits them for personal advantage, not revealing them to either to the general public or to the manufacturer.

17.3 Cyber Security and Threats

A cracker is someone who breaks into someone else's computer system, often on a network, bying s or licenses in computer programs.

Cyberattacks are launched primarily for causing significant damage to a computer system or for stealing important information from an individual or from an organization. Cyber security is a collection of various technologies, processes and measures that reduces the risk of cyber attacks and protects organizations and individuals from computer based threats.



Software cracking is the most often used type of cracking which is nothing but removing the encoded copy protection. There is another type of cracking called cracking. This is mainly used to crack the s. 189

Chapter 17 Pages 184-199.indd 189

02/08/18 2:56 PM

www.tn11th.in TYPES OF CYBER ATTACKS Malware is a type of software designed through which the criminals gain illegal access to software and cause damage. Various types of cyber-attacks and their functions are given inTable 17.2. Table 17.2 – Cyber Attacks and Functions S.No.

Cyber Attack

1.

Virus

2.

Worms

3.

Spyware

4.

Ransomware

Function A virus is a small piece of computer code that can repeat itself and spreads from one computer to another by attaching itself to another computer file. One of the most common virus is Trojan. Trojan A Trojan virus is a program that appears to perform one function (for example, virus removal) but actually performs malicious activity when executed. Worms are self- repeating and do not require a computer program to attach themselves. Worms continually look for vulnerabilities and report back to the author of the worm when weaknesses are discovered. Spyware can be installed on the computer automatically when the attachments are open, by clicking on links or by ing infected software. Ransomware is a type of malicious program that demands payment after launching a cyber-attack on a computer system. This type of malware has become increasingly popular among criminals and costs the organizations millions each year.

Cyber Security Threats

through tricks. Phishing and pharming are examples of social engineering.

In recent years, most of the individuals and enterprises are facing problems due to the weaknesses inherent in security systems and compromised organizational infrastructures. Different types of Cyber Security Threats are categorized as below:

Phishing Phishing is a type of computer crime used to attack, steal data, including name, and credit card numbers. It occurs when an attacker targets a victim into opening an e-mailor an instant text message. The attacker uses phishing to distribute malicious links or attachments that can perform a variety of functions,

Social engineering A misuse of an individual’s weakness, achieved by making them to click malicious links, or by physically accessing the computer 190

Chapter 17 Pages 184-199.indd 190

02/08/18 2:56 PM

www.tn11th.in Man In The Middle (MITM) :

including the extraction of sensitive credentials from victims.

Man-in-the-middle attack (MITM; also Janus attack) is an attack where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other.

PHISHING

This can lead to fraud or identity theft

s should always be cautious when opening emails or attachments

Example: Suppose Alice wishes to communicate with Bob. Meanwhile, Mallory wishes to intercept the conversation to overhear and optionally to deliver a false message to Bob.

Figure 17.4 Diagrammatic representation of Phishing

Alice

Mallory

Bob

Pharming Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting s to fraudulent web sites without their knowledge or permission. Pharming has been called "phishing without a trap”. It is another way hackers attempt to manipulate s on the Internet. It is a cyber-attack intended to redirect a website's traffic to a fake site.

Figure 17.6 - An illustration of the man-inthe-middle attack Cookies A cookie (also called HTTP cookie, web cookie, Internet cookie, browser cookie, or simply cookie) is a small piece of data sent from a website and stored on the 's computer memory (Hard drive) by the 's web browser while the is browsing internet. Cookies were designed to be a reliable mechanism for websites to stateful information (such as items added in the shopping cart in an online store) or to record the 's browsing activity (including clicking particular buttons, logging in etc.). They can also be used to arbitrary pieces of information that the previously entered into form fields such as names, addresses, s, and credit card numbers. From the security point of view, if cookie data is not encrypted,

PHARMING

This can lead to fraud or identity theft

s should always be cautious when opening emails or attachments

Figure 17.5 Diagrammatic representation of Pharming

191

Chapter 17 Pages 184-199.indd 191

02/08/18 2:56 PM

www.tn11th.in Firewall and Proxy Servers

any anonymous (hacker) can access the cookie information and misuse it.

A firewall is a computer network security based system that monitors and controls incoming and outgoing network traffic based on predefined security rules. A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network. They are generally categorized as network-based or host-based. Network based firewalls are positioned on the gateway computers of LANs [local area Network], WANs [Wide Area Network] and intranets. Host-based firewalls are positioned on the network node itself. The host-based firewall may be a service as a part of the operating system or an agent application such as endpoint security or protection. Each has advantages and disadvantages. However, each has a role in layered security. Firewalls also vary in type depending on where communication originates, where it is intercepted, and the state of communication being traced. Figure 17.7 shows the working of firewall server.

Web sites typically use cookies for the following reasons: • To collect demographic information about who has visited the Web site. • Sites often use this information to track how often visitors come to the site and how long they remain on the site. • It helps to personalize the 's experience on the Web site. • Cookies can help store personal information ers so that when a subsequently returns to the site, a more personalized experience is provided. If you ever returned to a site and have seen your name mysteriously appear on the screen, it is because on a previous visit, you gave your name to the site and it was stored in a cookie. A good example of this is the way some online shopping sites will make recommendations to s based on their previous purchases. It helps to monitor ments. Cookies do not act maliciously on computer system. They are merely text files that can be deleted at any time.

A proxy server acts as an intermediary between the endsand a web server. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resources available from a different server. The proxy server examines the request, checks authenticity and grants the request based on that. Proxy servers typically keep the frequently visited site addresses in its cache which leads to improved response time.

Cookies cannot be used to spread viruses and they cannot access your hard drive. However, any personal information that you provide to a Web site, including credit card information, will most likely be stored in a cookie unless the cookie feature is explicitly turned off in your browser. This is the way in which cookies threaten privacy.

Figure 17.8 shows the working of a proxy server. 192

Chapter 17 Pages 184-199.indd 192

02/08/18 2:56 PM

www.tn11th.in

Connection to internet (Point of vulnerability) Request Denied

LAN

Internet

Trusted s

R e q u e s t Permitted Firewall servers as a filter

Restricted Area

Unrestricted Area

Figure 17.7 Firewall Server web browser sends request s computer

web browser request forwarded web server

Proxy server

web server response is filtered

web servers send back response to proxy server

Figure 17.8 Working of Proxy server

Encryption and Decryption Encryption and decryption are processes that ensure confidentiality that only authorized persons can access the information.



Encryption is the process of translating the plain text data (plaintext) into random and mangled data (called cipher-text). Decryption is the reverse process of converting the cipher-text back to plaintext. Encryption and decryption are done by cryptography. In cryptography a key is a piece of information (parameter) that determines the functional output of a cryptographic algorithm. Figure 17.10 shows the encryption and decryption process. 193

Chapter 17 Pages 184-199.indd 193

02/08/18 2:56 PM

www.tn11th.in

Basic Encryption & Decryption Plain text

Plain text

Cipher text decryption

encryption

Figure 17.9 Encryption and Decryption Encryption has been used by militaries and governments to facilitate secret communication. It is now commonly used in protecting information within many kinds of civilian systems. It is also used to protect data in communication system, for example data being transferred via networks (e.g. the Internet, ecommerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines. There have been numerous reports of data in communication being intercepted in recent years. Data should also be encrypted when transmitted across networks in order to protect against the network traffic by unauthorized s. TYPES OF ENCRYPTION There are two types of encryption schemes as listed below: • Symmetric Key encryption • Public Key encryption SYMMETRIC KEY ENCRYPTION Symmetric encryption is a technique to use the same key for both encryption and decryption. The main disadvantage of the symmetric key encryption is that all authorized persons involved, have to exchange the key used to encrypt the data before they can decrypt it. If anybody intercepts the key information, they may read all message. Figure 17.10 depicts the working of symmetric key encryption.

Secret Key

Same Key

Secret Key

A4$h*L@9.

Encryption

T6=#/>B#1 Ro6/J2.>1L

Decryption

1PRL39P20

Plain Text

Cipher Text

Plain Text

Figure 17.10 Symmetric key encryption 194

Chapter 17 Pages 184-199.indd 194

02/08/18 2:56 PM

www.tn11th.in PUBLIC KEY ENCRYPTION Public key encryption isalso called Asymmetric encryption. It uses the concept of a key value pair, a different key is used for the encryption and decryption process. One of the keys is typically known as the private key and the other is known as the public key. The private key is kept secret by the owner and the public key is either shared amongst authorized recipients or made available to the public at large. The data encrypted with the recipient’s public key can only be decrypted with the corresponding private key. Figure 17.11 shows the public key encryption.

Encrypted document

Decrypted with recipient's private key Recipient

Sender

Plain text document

Decrypted with recipient's private key

Plain text document

Figure 17.11 Public key encryption Asymmetric Encryption in Digital Certificates: A digital certificate in a client-server model of communication is one of the example of Asymmetric Encryption. A certificate is a package of information that identifies a and a server. It contains information such as an organization’s name, the organization that issued the certificate, the s’ email address and country, and ’s public key. When a server and a client require a secure encrypted communication, they send a query over the network to the other party, which sends back a copy of the certificate. The other party’s public key can be extracted from the certificate. A certificate can also be used to uniquely identify the holder. Digital Signature Digital signatures are based on asymmetric cryptography and can provide assurances of evidence to origin, identity and status of an electronic document, transaction or message, as well as acknowledging informed by the signer. To create a digital signature, g software (email) creates a one-way hash of the electronic data to be signed. The 's private key to encrypt the hash, returning a value that is unique to the hashed data. The encrypted hash, along with other information such as the hashing algorithm, forms the digital signature. Any change in the data, even to a single bit, results in a different hash value. This attribute enables others to validate the integrity of 195

Chapter 17 Pages 184-199.indd 195

02/08/18 2:56 PM

www.tn11th.in the data by using the signer's public key to decrypt the hash. If the decrypted hash matches a second computed hash of the same data, it proves that the data hasn't changed since it was signed. If the two hashes don't match, the data has either been tampered with in some way (indicating a failure of integrity) or the signature was created with a private key that doesn't correspond to the public key presented by the signer (indicating a failure of authentication). Figure 17.12 shows the function of a digital signature.

Message Sender

Message, Digital Signature and Sender X.509

Create Signature

Message

Signature

Recipient

Different keys are used to create and Digital Signature

Sender Private Key

Sender Public Key

Figure 17.12 –Function of Digital Signature

17.4 INTRODUCTION TO INFORMATION TECHNOLOGY ACT In the 21stcentury, Computer, Internet and ICT or e-revolution has changed the life style of the people. Today paper based communication has been substituted by e-communication. Accordingly we have new terminologies like cyber world, e-transaction, e-banking, e-return and e-contracts. Apart from positive side of e-revolution there is also negative side of computer, that is, the internet and ICT in the hands of criminals which has become a weapon of offence. Accordingly a new of emerged to tackle the problems of cyber crimes in cyber space i.e. Cyber Law or Cyber Space Law or Information Technology Law or Internet Law. In India Cyber law and IT Act 2000 , modified in 2008 are being articulated to prevent computer crimes. IT Act 2000 is an act to provide legal recognition for transactions carried out by means of ElectronicData Interchange(EDI) and other means of electronic communication. It is the primary law in India dealing with cybercrime and electronic commerce(e-Commerce). e-Commerce is electronic data exchange or electronic filing of information. “Cyber law or Internet law is a term that encapsulates the legal issues related to use of the Internet. 196

Chapter 17 Pages 184-199.indd 196

02/08/18 2:56 PM

www.tn11th.in PREVENTION 25% of cyber crime remains unsolved. To protect the information the following points to be noted: • Complex setting can make your surfing secured. • When the internet is not in use, disconnect it. • Do NOT open spam mail or emails that have an unfamiliar sender. • When using anti-virus software, keep it up-to-date.

• Awareness is the key to security • Information security is the immune system in the body of business. • A check that does not bounce is called the Security Check. Do it every day before you leave! • Do Your Part - Be Security Smart !!! • Don’t be Quick to Click… be wary when you shop online. • Restart is Smart job • s are like toothbrushes. They are best when new and should never be shared. • When you and your system part away, your system should be first off for the day. • Your mind is a storage room of information, keep the door locked. • _ a _ _word is not a without Protect, Save and Secure! • Link Link stop neglect….Think Think before connect…..

Evaluation Part I Choose the correct Answer: 1.

Which of the following deals with procedures, practices and values? a. piracy b. programs c. virus d. computer ethics

2.

Commercial programs made available to the public illegally are known as a. freeware b. warez c. free software d. software

3. Which one of the following are self-repeating and do not require a computer program to attach themselves? a. viruses b. worms c. spyware d. Trojans 4. 5.

Which one of the following tracks a visits a website? a. spyware b. cookies c. worms d. Trojans Which of the following is not a malicious program on computer systems? a. worms d. Trojans c. spyware d. cookies 197

Chapter 17 Pages 184-199.indd 197

02/08/18 2:56 PM

www.tn11th.in 6. A computer network security that monitors and controls incoming and outgoing traffic is a. Cookies b.Virus c. Firewall d. worms 7.

The process of converting cipher text to plain text is called a. Encryption b. Decryption c. key d. proxy server

8.

e-commerce means a. electronic commerce c. electric data exchange

9.

Distributing unwanted e-mail to others is called. a. scam b. spam c. fraud d. spoofing

10.

Legal recognition for transactions are carried out by a. Electronic Data Interchange b. Electronic Data Exchange c. Electronic Data Transfer d. Electrical Data Interchange

b. electronic data exchange d. electronic commercialization.

Part II Answer to the following questions (2 Marks): 1. 2. 3. 4. 5.

What is harvesting? What are Warez? Write a short note on cracking. Write two types of cyber attacks. What is a Cookie?

Part III Answer to the following questions (3 Marks): 1. 2. 3. 4. 5.

What is the role of firewalls? Write about encryption and decryption. Explain symmetric key encryption. What are the guidelines to be followed by any computer ? What are ethical issues? Name some.

Part IV Answer to the following questions (5 Marks): 1. 2. 3.

What are the various crimes happening using computer? What is piracy? Mention the types of piracy? How can it be prevented? Write the different types of cyber attacks.

Reference Books : • Computer Network Security and Cyber Ethics by Joseph MiggaKizza • “Investigating Cyber Law and Cyber Ethics: Issues, Impacts and Practices: 1” by Alfreda Dudley and James Braman 198

Chapter 17 Pages 184-199.indd 198

02/08/18 2:56 PM

www.tn11th.in

GLOSSARY

WORD Vulnerability Ethics Cyber Computer Crime Authenticity Sabotage Perpetrator Software Piracy Hacking Cracking Malicious Freeware Shareware Phishing Fraudulent Anonymous Cookies Tampering Immune Firewall Proxy server Encryption Decryption

MEANING The possibility of being attacked or harmed. Moral principles that govern a person's behaviour or the conducting of an activity. Characteristic of the culture of computers, information technology, and virtual reality. Computer crime is an intellectual crime to manipulate computer system. The quality of being real or true. Deliberately destroy, damage, or obstruct. A person who carries out a harmful, illegal, or immoral act. Software Piracy is the copyright violation of software created originally by one person and illegally used by someone else. Hacking is gaining unauthorized access to s computer system without the owner’s permission. Cracking is gaining unauthorized access to computer systems to commit a crime, such as stealing the code to make a copy-protected program run thus denying service to legitimate s. Intentionally doing harm. Freeware is a software available free of charge. Shareware is a software that is distributed free of charge on a trial basis for a limited time. Phishing is a term used to describe a malicious individual or group of individuals who scam s by sending e-mails or creating web pages that are designed to collect an individual's online bank, credit card, or other information. Dishonest, cheating, swindling, corrupt, criminal, illegal, unlawful. 1 Unnamed, nameless, unidentified, unspecified. Cookies are messages that web servers to your web browser when you visit Internet sites Interfere in order to cause damage. Resistant to a particular infection or toxin. A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A proxy server is a gateway between a local network and a larger-scale network such as the Internet. Proxy servers provide increased performance and security. Encryption is the process of encoding a message or information so that only authorized s can decrypt it Decryption is theprocess of decoding the encrypted text by converting it back into normal text. 199

Chapter 17 Pages 184-199.indd 199

02/08/18 2:56 PM

www.tn11th.in

Unit V

Tamil Computing

CHAPTER

18

Tamil Computing 18.1 Introduction “ பிறநாட்டு நல்லறிஞர் சாத்திரங்கள் தமிழ்மொழியிற் பெயர்த்தல் வேண்டும்; இறவாத புகழுடைய புதுநூல்கள் தமிழ்மொழியில் இயற்றல் வேண்டும்; மறைவாக நமக்குள்ளே பழங்கதைகள் ச�ொல்வதில�ோர் மகிமை இல்லை; திறமான புலமையெனில் வெளிநாட்டோர்; அதை வணங்கஞ் செய்தல் வேண்டும்.” – மகாகவி பாரதி

Human civilization developed with the innovation of computer in the twentieth century. Computer development began as the early calculating tool that was essential ingredient for gigantic growth for the existence of human life without computers. It is true that any language will be outdated when it does not have the ability to adapt itself to the changing technologies. Tamil is the living language for thousands of years. Development of modern technologies, does not affect the growth of classical Tamil as it is ready to adopt the growing technological changes. Tamil is not just a language, it is our identity, our life and our sense. “எங்கள் வாழ்வும், எங்கள் வளமும் மங்காத தமிழென்று சங்கே முழங்கு” – புரட்சி கவி.

18.2 Tamil in Internet We know that the internet today is a plays a vital role in every man's life. Internet is the best information technological device, through which we get know everything from Internet . In 2017 a study conducted by KPMG a Singapore based organizationalong with google, reported that, Tamil topped the list, among the most widely used languages in India where 42% are using the Internet in Tamil

200

Chapter 18 Pages 200-209.indd 200

02/08/18 3:03 PM

www.tn11th.in

Figure: 18.1 Moreover in 2021 onwards, 74% of people in India will access internet using Tamil and it will be in the top usage of Internet in India.

Figure: 18.2 These statistical data will be useful to improve internet services in Tamil.

201

Chapter 18 Pages 200-209.indd 201

02/08/18 3:03 PM

www.tn11th.in 18.3 Search Engines in Tamil The “Search Engines” are used to search any information from the cyber space. Although there are many search engines, but only a few of them are frequently in use. In the top ten search engines, Google, Bing and Yahoo are takes first three places respectively. Google and Bing provide searching facilities in Tamil, which means you can search everything through Tamil. A Google search engine gives you an inbuilt Tamil virtual keyboard.

உள்ளீட்டுக் கருவிகள்

Figure: 18.3 (a) Google Search Engine (India)

உள்ளீட்டுக் கருவிகள்

Figure 18.3(b) Google Search Engine (Singapore)

202

Chapter 18 Pages 200-209.indd 202

02/08/18 3:03 PM

www.tn11th.in

Figure: 18.4 Searching in Tamil 18.4 e – Governance: Getting Government services through internet is known as e-Governance. Govt. of Tamilnadu has been giving its services through Internet. One can communicate with Govt. of Tamilnadu from any corner of the state. One can get important announcements, government orders, and government welfare schemes from the web portal of Govt. of. Tamilnadu.

Figure: 18.5 Official Website of Govt. of Tamilnadu 203

Chapter 18 Pages 200-209.indd 203

02/08/18 3:03 PM

www.tn11th.in Table : 18.1 E-Governance through Tamil Official Website of Govt. of Tamilnadu Department of Agricultural Engineering Department of Environment Directorate of Govt. Examinations Tamilnadu Health Department Tamilnadu Micro, Small and Medium Enterprises Department Rural Development and Panchayat Raj Department Backward, Most Backward and Minorities Welfare Department Tamilnadu Forest Department Hindu Religious and Charitable Endowments Department. Tamil Nadu Public Service Commission (TNPSC) Official Website of Govt. of Srilanka

Web Address http://www.tn.gov.in/ta http://www.aed.tn.gov.in/ http://www.environment.tn.nic.in/ http://www.dge.tn.nic.in/ http://www.tnhealth.org/ http://www.msmeonline.tn.gov.in/ http://www.tnrd.gov.in/ http://www.bcmbcmw.tn.gov.in/ https://www.forests.tn.gov.in/ http://www.tnhrce.org/ http://www.tnpsc.gov.in/tamilversion/index. html https://www.gov.lk/index.php

Outside India, Government of Srilanka provides all their services through the official website in Tamil. 18.5 e-Library E-Libraries are portal or website of collection of e-books. Tamil e-Library services provide thousands of Tamil Books as ebooks mostly at free of cost. It is the most useful service to Tamil people who live far away from their home land. Table : 18.2 Tamil e-Library Tamilnadu School Education and Teacher Education Training Textbooks and Resource Books Tamil Virtual Academy Connemara Public Library Tamil Digital Library Chennai Library Thamizhagam

Website address http://www.textbooksonline.tn.nic.in/ http://www.tamilvu.org/library/libindex.htm http://connemarapubliclibrarychennai.com/ Veettukku_oru_noolagam/index.html http://tamildigitallibrary.in/ http://www.chennailibrary.com/ http://www.thamizhagam.net/parithi/ parithi.html 204

Chapter 18 Pages 200-209.indd 204

02/08/18 3:03 PM

www.tn11th.in

Project Madurai Old Books and Manuscripts Noolaham Anna Centenary Library

http://www.projectmadurai.org/pmworks. html http://www.tamilheritage.org/old/text/ ebook/ebook.html http://www.noolaham.org/wiki/index.php/ http://www.annacentenarylibrary.org/

18.6 Tamil Typing and Interface software Tamil is mostly used to type documents in word processors and search information from internet. Typing Tamil using Tamil interface software is the familiar one among the different methods of typing. This is the simplest method of typing Tamil in both Computer and Smart phones. 18.6.1 Familiar Tamil Keyboard Interface: • NHM Writer, E-Kalappai and Lippikar – are familiar Tamil keyboard interfaces software that is used for Tamil typing which works on Tamil Unicode, using phonetics. • Sellinam and Ponmadal – are familiar Tamil keyboard layouts that works on Android operating system in Smart phone using phonetics.

Figure: 18.6 eKalappai Opening screen 18.7 Tamil Office Automation Applications Famous Office automation software like Microsoft Office, Open Office etc., provides complete Tamil interface facility. These softwares are able and installed in your computer. After installation, your office automation software environment will completely 205

Chapter 18 Pages 200-209.indd 205

02/08/18 3:03 PM

www.tn11th.in changed to Tamil. Menu bars, names of icons, dialog boxes will be shown in Tamil. Moreover, you can save files with Tamil names and create folders with Tamil names.

Figure 18.7: Libra Office Writer Environments in Tamil Apart from that Tamil Libra Office, Tamil Open Office, Azhagi Unicode Editor, Ponmozhi, Menthamiz, Kamban, Vani are office automation software working exclusively for Tamil. You can these applications are designed to work completely in Tamil. 18.8 Tamil Translation Applications Thamizpori (தமிழ்பொறி) is a Tamil translation application having more than 30000 Tamil words equalent to English words. Using this application, we can transalte small english sentences into Tamil. Google also gives an online translation facility, using this online facility we can translate from Tamil to any other language vice versa. 18.9 Tamil Programming Language Programming languages to develop software to computers and smart phones are available only in English. Now, efforts are taken to develop programming languages in Tamil. Based on Python programming language, the first Tamil programming language “Ezhil” (எழில்) is designed. With the help of this programming language, you can write simple programs in Tamil. 206

Chapter 18 Pages 200-209.indd 206

02/08/18 3:03 PM

www.tn11th.in 18.10 Tamil Information Interchange Coding Systems TSCII (Tamil Script Code for Information Interchange) Computers are handle data and information as binary system. Every data should be converted into binary while it is feed into a computer system. You learnt about all these things in the first unit of this text book. Computers use ASCII encoding system to handle data and information. The ASCII encoding system is applicable only for handling English language. Therefore, TSCII (Tamil Script Code for Information Interchange) is the first coding system to handle our Tamil language in an analysis of an encoding scheme that is easily handled in electronic devices, including non-English computers. This encoding scheme was ed in IANA (Internet Assigned Numbers Authority) unit of ICANN. ISCII (Indian Script Code for Information Interchange) This is one of the encoding schemes specially designed for Indian languages including Tamil. It was unified with Unicode. Unicode: Unicode is an encoding system, designed to handle various world languages, including Tamil. Its first version 1.0.0 was introduced on October 1991. While introduction of this scheme, can be able to handle nearly 23 languages including Tamil. Among the various encoding scheme, Unicode is the suitable to handle Tamil. 18.11 Tamil Operating System An operating system is needed to access electronic systems such as computer and smart phone. Microsoft Windows is very popular operating system for personal computers. Linux is another popular open source operating system. Operating systems are used to access a computer easily. An operating system should be easy to work and its environment should be in understandable form. Thus, all operating systems used in computers and smart phones offered environment in Tamil. Windows Tamil Environment interface should be ing and install from internet. It shows all windows elements such as Taskbar, desktop elements, names of icons, commands in Tamil. 18.12 Organisation and projects to develop Tamil Tamil Virtual Academy: With the objectives of spreading Tamil to the entire world through internet, Tamil Virtual University was established on 17th February 2001 by the Govt. of Tamilnadu. Now, this organisation functioning with the name “Tamil Virtual Academy”. This organisation offers different courses regarding Tamil language, Culture, heritage etc., from kindergarten to under graduation level. 207

Chapter 18 Pages 200-209.indd 207

02/08/18 3:03 PM

www.tn11th.in Website: http://www.tamilvu.org/index.php Tamil Language Council, Singapore With the objectives of promoting the awareness and greater use of Tamil among the Singaporeans, in 2001 the council of Tamil Language was formed by the ministry of Information Communications and Arts, Govt. of Singapre. The council is called as “வளர்தமிழ் இயக்கம்”.

Website: http://tamil.org.sg/ta Madurai Project Project Madurai is an open and voluntary initiative to collect and publish free electronic editions of ancient tamil literary classics. This means either typing-in or scanning old books and archiving the text in one of the most readily accessible formats for use on all popular computer platforms. Since its launch in 1998, Project Madurai released in Tamil script form as per TSCII encoding. Since 2004 they started releasing ebooks in Tamil unicode as well. Web Site: http://www.projectmadurai.org/ Tamil Wikipedia: Wikipedia is a open source encyclopedia. Any person can write article about any subject. In Tamil Wikipedia has more than 1 lacks articles. Web Site: https://ta.wikipedia.org/

In order to make Tamil as a living language, it is the duty every Tamilian to make 208

Chapter 18 Pages 200-209.indd 208

02/08/18 3:03 PM

www.tn11th.in participate Tamil in development of technology. Those who forgotten their values, they will be considered as “Nomads”. If we learn about how many great technologies we have to add Tamil as a symbol of our race. It is our duty to combine our world's first language and language for more than five thousand years with growing technology. Points to : • Tamil topped the list of the most widely used languages in India by the end of 2016, while 42% are using the Internet. • Google and Bing provide searching facilities in Tamil. • Getting Government services through internet is known as e-Governance. • Tamil e-Library services provide thousands of Tamil Books as ebooks mostly at free of cost. • Thamizpori (தமிழ்பொறி) is a Tamil tranlation application having more than 30000 Tamil words equalent to English words. • The first Tamil programming language is “Ezhil” (எழில்) • Unicode is an encoding system, designed to handle various world languages, including Tamil. • Among the various encoding scheme, Unicode is the suitable to handle Tamil. • Windows Tamil Environment interface should be ing and install from internet.

Evaluation Answer to the following questions 1. List of the search engines ing Tamil. 2. What are the keyboard layouts used in Android? 3. Write a short note about Tamil Programming Language. 4. What TSCII? 5. Write a short note on Tamil Virtual Academy. ****

209

Chapter 18 Pages 200-209.indd 209

02/08/18 3:03 PM

www.tn11th.in

COMPUTER APPLICATIONS – XI Vol-II List of Authors and Reviewers Domain Experts

Authors

Mrs. Bagyalakshmi P. Asst. Professor and Head of the Department, Dept. of Computer Applications, Queen Mary’s College, Chennai.

Mr. Ramakrishnan V. G. Post Graduate Teacher, Karnataka Sangha Hr Sec School, T.Nagar, Chennai.

Reviewers

Mr. Kannan K. Post Graduate Teacher, Chennai Girls Hr. Sec School, Rotler Street, Chennai.

Dr. T.V. Gopal  Professor, Dept. of Computer Science and Technology, College of Engineering, Guindy, Anna University, Chennai. Dr. Ranjani Parthasarathi Professor, Dept. of Info Science and Technology, College of Engineering, Guindy, Anna University, Chennai.

Content Experts Dr. Radha P Assistant Professor, Dept. of Information Technology, Govt. Arts & Science College (A), Coimbatore. Dr. Nester Jeyakumar M Associate Professor and Head of the Department, Dept. of Computer Science, Loyola College, Chennai.

Mrs. Bindhu Mohandas Post Graduate Teacher, Vijayanta Model Hr. Sec. School, H.V.F Estate, Avadi, Chennai. Mr. Gowrisankar N.V. Post Graduate Teacher, Chennai Girls Hr. Sec School, Nungambakkam, Chennai. Mr. Sreenivasan R. Post Graduate Teacher, Santhome Hr. Sec. School, Mylapore, Chennai. Mr. Lenin K. Post Graduate Teacher, Chennai Girls Hr Sec School, Saidapet, Chennai Miss. Sangeetha A. Post Graduate Teacher, Govt. Hr. Sec. School, Rajanthangal, Thiruvannamalai. Dr. Valarmathi K.E. Post Graduate Teacher, Academic Council, Velammal Vidhyashram, Surapet, Chennai. Mrs. Gajalakshmi R. Post Graduate Teacher, Jaigopal Garodia Hindu Vidyalaya Hr. Sec School, West Mambalam, Chennai. Mrs. Vidhya H. Post Graduate Teacher, DAV Boys Senior Seconary School, Gopalapuram, Chennai.

Academic Coordinators Mr. Ravikumar Arumugam Deputy Director, State Council of Educational Research and Training, Chennai.

Art and Design Team Layout THY Designers and Computers Chennai

QC Manohar Radhakrishnan Gopu Rasuvel Wrapper Design Kathir Arumugham Co-ordination Ramesh Munisamy Typist T. Meena

Mrs. Tamil Selvi R. B.T. Assistant, Government High School, Poonampalayam, Trichy Dist.

QR Code Team R. Jaganathan, S.G.T., PUMS, Ganesapuram- Polur, Thiruvannamalai Dist. N. Jagan, B.T. Asst., GBHSS, Uthiramerur, Kancheepuram Dist. J.F. Paul Edwin Roy, B.T. Asst., PUMS, Rakkipatti, Salem Dist.

This book has been printed on 80 G.S.M. Elegant Maplitho paper. Printed by offset at:

210 Acknowledgement.indd 210

02/08/18 5:33 PM

---

Related Documents

11th Std-computer Applications Vol-ii Em - Www.tn11th.in

August 2021 0

11th Standard Complete Em Notes (1)

December 2021 0

11th Physics Slow Learners Study Material Em

December 2019 194

11th - ancy

December 2019 57

Applications

November 2022 0

Stat11t_formulas-triola 11th Ed.

December 2021 0

---

More Documents from "archana"

11th Std-computer Applications Vol-ii Em - Www.tn11th.in

August 2021 0

Mango

March 2021 0

Case Study

December 2019 70

Latest Advancements In Microprocessor

November 2019 46

Hard Disk Price In Nehru Place Market Delhi - Usb Hard Disk Price In India, Internal Ssd & External Hdd Rate List

December 2019 59

Hr Ppt Final

April 2022 0

Copyright © 2025 IDOUB.