Java script

JAVASCRIPT

Prof. AshishSingh Bhatia

Brief History

December 4, 1995 Netscape and Sun introduced JavaScript 1.0, called LiveScript.

Netscape Navigator 2

LiveScript JavaScript

Microsoft joins in with IE 3 called it Jscript.

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Prof. Ashish Bhatia

What is JavaScript

Interpreted Language

Object-Based

Cross Platform

Loosely Typed

Multi Use Language

Client Side interpreted.

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Advantage of JavaScript

An Interpreted Language

Embedded within HTML

Minimal Syntax – Easy to learn

Quick Development

Design for Simple, Small Programs

Performance

Procedural Capabilities

Designed for Programming User Events

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Prof. Ashish Bhatia

Advantage of JavaScript

Easy Debugging and Testing

Platform Independence / Architectural Neutral

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How to add JS in HTML

<script language=“javascript”>Java Script Code

</script>

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Data Type

4 primitive data types

Number

Integer, Floating Number, NaN

Boolean

True and false [ 1 and 0 ]**

String

Null

A null , empty or nonexistent reference

Complex Types like array and objects

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Creating Variables and Array

var <variable name> = value; arrayName = new Array(); arrayName = new Array(length); Index starts with 0 join() and reverse() length

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Variable Name

Can Begin with

A to Z

a to z

_

$

Case Sensitive

variableName

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Operator

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Arithmetic Operator

+ , - , * , / , % , ++ , --

Logical Operator

&&, || , !

Comparison Operator

== , === , != , !== , < , > , <= , >=

Assignment Operator

= , += , -= , *= , /= , %=

Ternary Operator

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Condition ? Value 1 : value 2

Special Operator

delete : Delete property of an object or an element at an array index

new : Create an instance of an Object type

void : Does not return a value.

Programming Constructs

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Assignment x = x+y;

Data declaration var x = 5;

If

Switch

While

For

Do while

Label LabelName: Statement

Programming Constructs

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break

continue

function call x = abs(y);

return

with with(Math){ }

delete delete a[5]

Method Invocation document.write(“Hello”);

Functions in JavaScript

Prof. Ashish Bhatia

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Built-in Function

eval() paresInt(), parseFloat()

User Defined Function

function function_name(parameter1, parameter2..)

{block of JavaScript Code

}

Dialog Boxes

Prof. Ashish Bhatia

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AlertUsed to display a small textual output with ok

button.

Prompt Displays a predefined message

Displays a text box and accepts user input

Display ok and cancel buttonOk text from text box is passed to the program

environment

Cancel passes NULL value to the program environment.

Dialog Boxes

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Confirm

Predefined message

OK and Cancel button

OK passes TRUE to the program

Cancel passes FALSE to the program

Example of Alert

Prof. Ashish Bhatia

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Example of Alert

Prof. Ashish Bhatia

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Example of Alert

Prof. Ashish Bhatia

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Youtube channel

Prof. Ashish Bhatia

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http://www.youtube.com/profashish

Slideshare

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http://www.slideshare.net/ashishsinghbhatia