4. Why ? - Naive User
Where ? - Internet [From Anywhere]
What? - Pictures are better way to express
communication than letters or journals
How? - HTML/CSS/JS
10. ● Everything is a Object eg function , var
anything(Native/Host)
● There are also these primitive
value types like Undefined, Null,
String, Boolean and Number that
aren't objects
● JS is Object-oriented language or Prototype
based language
11. "Prototype-based programming is a style of
object-oriented programming in which
classes are not present, and behavior reuse
(known as inheritance in class-based
languages) is accomplished through a process
of decorating existing objects which serve
as prototypes. This model is also known as
class-less, prototype-oriented, or instancebased programming."
12. Prototype
● When you define a function within
JavaScript, it comes with a few pre-defined
properties
● The prototype property is initially an empty
object, and can have members added to it –
as you would any other object.
● Every object within JavaScript has a “secret”
property added to it when it is defined or
instantiated, named __proto__
● __proto__ property shouldn’t be confused
with an object’s prototype
13. var redbus = function(address){
this.address = "honolulu";
return this.address;
}
console.log(typeof redbus) //FUNCTION
"Function is a predefined object in
JavaScript, and, as a result, has its own
properties (e.g. length and arguments) and
methods (e.g. call and apply). And yes, it,
too, has its own prototype object, as well as the
secret __proto__ link."
15. This is known as prototype chain!
● Ends when prototype of any object is null
● By default Object's prototype is null
● Confusing - Yes , Everything is Object and
Function , no classess , no keywords as
public - private: "yet we challenge to make it
Object Oriented"
17. / inherit Person
Monkey.prototype = new Animal();
Monkey.prototype.constructor = Monkey;
Monkey.prototype.sing = function(){
alert('Sing like OM');
}
var vishal = new Monkey();
vishal.walk(); vishal.sing();
18. This is Inheritance !
Can be checked by.
console.log(vishal instanceof Animal) // true
console.log(vishal instanceof Monkey) // true
In modern browser this can be achieved by:
Monkey.prototype = Object.create
(Animal.prototype);
19. Closures.
The pattern of public, private, and privileged
members is possible because JavaScript
has closures.
20. function Container(param) {
function dec() {
//uses secret
} //privileged
this.member = param;//public
var secret = 3;//private
var that = this;
this.service = function () {
return dec() ? that.member : null;
};//public
}
21. Enough OOPS!
Hoisting
● Function level scoping not block level like
C++, Java, C#
● Function declarations and variable
declarations are always moved (“hoisted”)
invisibly to the top of their containing scope
by the JavaScript interpreter. eg.
22. Memory Leaks
● garbage collection
● mark and sweep algorithm
● reason for memory leaks
● IE - Ohh yeah :P
● Possible scenarios
