This document provides an overview of JavaScript, comparing it to Java and describing its main features. JavaScript is a lightweight, interpreted scripting language best known for powering interactive effects within web pages. Unlike Java, it is not a standalone programming language but rather is used to customize pages and validate form input based on user actions. The document goes on to describe JavaScript's data types, objects, arrays, functions, scope, closures, and use of regular functions versus constructors.

1. JAVASCRIPT

2. Java vs JavaScript
 Java - Programming Language (PL)
 Interactive Web Graphics
 Creating web browser applications
 Writing stand-alone applications
 JavaScript - Scripting Language
 Runs within the context of the Web browser
 Customizing pages based on browser version
 Visual Feedback to user actions
 Validating data entered on HTML Forms
 In reality, Java and JavaScript are unrelated…

3. PL versus SL – By Definition
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4. PL versus SL – By Type
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5. PL versus SL – By Interpretation
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6. PL versus SL – By Conversion
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7. PL versus SL - Examples
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8. Javascript(JS)
 Lightweight, interpreted, object oriented language with first class
functions and its best knows as scripting language for web pages
 Light weight- Small memory footprint, easy to implement
 interpreted- Instruction executed directly
 object oriented – Model around objects
 first class function – functions can be used as value

9. History
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10. Why JS
 Client side web development (Navigators Javascript)
 Native JS- not a framework
 JQuery – Library
 Angular JS, React JS, Ember JS – advance client side application
framework
 Server side web development (Live wire Javascript)
 Node JS
 Express JS (works with node)
 Desktop , mobile and browser extensions(add-on and
plug-in)
 RTE - browser

11. Data Types
 Number
 String
 Boolean
 Undefined
 Null
 Symbol

12. Type coersion
 Explicit coersion
 Implicit coersion
 Every value in javascript has boolean value

13. Objects*
 Free form – not bound to any class
 Object literal to create object
 Property of object can be accessed directly
 New property can be added directly on objects
 Objects can have methods
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 Dot notation versus [ ] notation

14. Array
 ARRAY IS SECRETLY AN OBJECT
Eg: var myArray=[“Hi”,”1”,”Hello”];
myArray[0] and myArray[“0”] results same
o/p
 length property(checking the index not the
count)

15. Function
 Function Declaration
 Function with args
 Function with return
 Function expression
 Anonymous function expression
 Function as args
 Function as Objects

16. Scope and Closure
 Scope
Scope is based on function
Not all variables are accessible anywhere
Global function vs IIFE
Read vs Write
Compilation vs Interpretation
 Closure
Module pattern

17. Regular fn vs Constructor
 Functions are objects
 Dunder proto
 Inheritance