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JQUERY – INTERMEDIATE

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ROAD MAP

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)

3ALLONGE (FRENCH) = ELONGATE

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JS – PRESENT, PAST & FUTUREJava Script

jQuery, Mootools, YUI etc(Client Side Framework)

MVC (Model, View & Controller)

Client Side Server Side

Angular JS(By Google)Backbone JS

etc

Node JSNarwhal

etc

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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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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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VALUES & IDENTITY

var n = "1";

console.log(n==1);

console.log(n===1);

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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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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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OBJECT

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DELEGATION

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DELEGATION OF MESSAGES

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VARIABLE SCOPE

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CLOSURES

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EXAMPLE FOR CLOSURES

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HOW CLOSURES WORKS?

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