This document provides an overview of jQuery and JavaScript concepts for intermediate learners. It covers: 1) the past, present and future of JavaScript, 2) the difference between JavaScript and jQuery, 3) what a JavaScript engine is and examples of engines used in different browsers, and 4) key JavaScript concepts like values and identity, prototypes vs classes, objects, delegation, closures, and variable scope. The document is intended to expand understanding of JavaScript and jQuery beyond basic usage.

1. JQUERY – INTERMEDIATE
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2. ROAD MAP
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1. JS - Present, Past & Future
2. Javascript Vs jQuery
3. JS Engine
4. Value & Identity
5. Class Vs Prototype
6. Object
7. Delegation
8. Closures
9. DOM & Left things (Next Time)

3. ALLONGE (FRENCH) = ELONGATE
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JS – PRESENT, PAST & FUTURE
jQuery, Mootools, YUI etc(Client Side Framework)
Client Side Server Side
Angular JS(By Google)
Backbone JS
etc
Node JS
Narwhal
etc

5. WHAT WE CAN NOT DO IN JS
- File I/O
- Using Ajax, JavaScript can send a request to the server. This
request can read a file in XML or plain text format but it cannot write
to a file unless the file called on the server actually runs as a script
to do the file write for you.
- Networking
- DB APIs
- unless you use Ajax and have a server side script perform the
database accesses for you.
- So, Node or other JSs has come.
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7. WHAT IS JAVASCRIPT ENGINE ?
A JavaScript engine is process virtual machine which interprets
and executes JavaScript (also known as ECMAScript).
Source – WiKi
Web Browsers Engine Used
FF SpiderMonkey
Chrome V8
Safari JavascriptCore
IE Chakra
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8. VALUES & IDENTITY
var n = "1";
console.log(n==1);
console.log(n===1);
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9. JAVASCRIPT BY OOPS, BUT NOT
"CLASS"-ICAL LANGUAGES.
- Object-Oriented
- Class – Object Relation
- But there are no classes in JavaScript. Functions can be
used to somewhat simulate classes.
- And when it comes to inheritance, objects inherit from
objects, not classes from classes as in the "class"-ical
languages.
- So, Java Script is NOT a "class"-ical languages.
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10. CLASS VS PROTOTYPE
- Yes, there are no classes in JavaScript.
- But Functions can be used to somewhat simulate classes.
- A drawback of CLASS is that the method getInfo() is
recreated every time you create a new object.
- A more inexpensive way is to add getInfo() to the
prototype of the constructor function.
- Class - Based :
- Code reuse through Inheritance
- Class - Object communication
- Prototype - Based :
- Code reuse through delegation
- Class - Object communication
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11. OBJECT
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12. DELEGATION
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13. DELEGATION OF MESSAGES
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14. VARIABLE SCOPE
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15. CLOSURES
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16. EXAMPLE FOR CLOSURES
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17. HOW CLOSURES WORKS?
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