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Property of object not returning the expected value in Javascript [duplicate]

In C++, the language I'm most comfortable with, usually one declares an object like this:
class foo
{
public:
int bar;
int getBar() { return bar; }
}
Calling getBar() works fine (ignoring the fact that bar might be uninitialized). The variable bar within getBar() is in the scope of class foo, so I don't need to say this->bar unless I really need to make it clear that I'm referring to the class' bar instead of, say, a parameter.
Now, I'm trying to get started with OOP in Javascript. So, I look up how to define classes and try the same sort of thing:
function foo()
{
this.bar = 0;
this.getBar = function() { return bar; }
}
And it gives me bar is undefined. Changing the bar to this.bar fixes the issue, but doing that for every variable clutters up my code quite a bit. Is this necessary for every variable? Since I can't find any questions relating to this, it makes me feel like I'm doing something fundamentally wrong.
EDIT: Right, so, from the comments what I'm getting is that this.bar, a property of an object, references something different than bar, a local variable. Can someone say why exactly this is, in terms of scoping and objects, and if there's another way to define an object where this isn't necessary?

JavaScript has no classes class-based object model. It uses the mightier prototypical inheritance, which can mimic classes, but is not suited well for it. Everything is an object, and objects [can] inherit from other objects.
A constructor is just a function that assigns properties to newly created objects. The object (created by a call with the new keyword) can be referenced trough the this keyword (which is local to the function).
A method also is just a function which is called on an object - again with this pointing to the object. At least when that function is invoked as a property of the object, using a member operator (dot, brackets). This causes lots of confusion to newbies, because if you pass around that function (e.g. to an event listener) it is "detached" from the object it was accessed on.
Now where is the inheritance? Instances of a "class" inherit from the same prototype object. Methods are defined as function properties on that object (instead of one function for each instance), the instance on which you call them just inherits that property.
Example:
function Foo() {
this.bar = "foo"; // creating a property on the instance
}
Foo.prototype.foo = 0; // of course you also can define other values to inherit
Foo.prototype.getBar = function() {
// quite useless
return this.bar;
}
var foo = new Foo; // creates an object which inherits from Foo.prototype,
// applies the Foo constructor on it and assigns it to the var
foo.getBar(); // "foo" - the inherited function is applied on the object and
// returns its "bar" property
foo.bar; // "foo" - we could have done this easier.
foo[foo.bar]; // 0 - access the "foo" property, which is inherited
foo.foo = 1; // and now overwrite it by creating an own property of foo
foo[foo.getBar()]; // 1 - gets the overwritten property value. Notice that
(new Foo).foo; // is still 0
So, we did only use properties of that object and are happy with it. But all of them are "public", and can be overwritten/changed/deleted! If that doesn't matter you, you're lucky. You can indicate "privateness" of properties by prefixing their names with underscores, but that's only a hint to other developers and may not be obeyed (especially in error).
So, clever minds have found a solution that uses the constructor function as a closure, allowing the creating of private "attributes". Every execution of a javascript function creates a new variable environment for local variables, which may get garbage collected once the execution has finished. Every function that is declared inside that scope also has access to these variables, and as long as those functions could be called (e.g. by an event listener) the environment must persist. So, by exporting locally defined functions from your constructor you preserve that variable environment with local variables that can only be accessed by these functions.
Let's see it in action:
function Foo() {
var bar = "foo"; // a local variable
this.getBar = function getter() {
return bar; // accesses the local variable
}; // the assignment to a property makes it available to outside
}
var foo = new Foo; // an object with one method, inheriting from a [currently] empty prototype
foo.getBar(); // "foo" - receives us the value of the "bar" variable in the constructor
This getter function, which is defined inside the constructor, is now called a "privileged method" as it has access to the "private" (local) "attributes" (variables). The value of bar will never change. You also could declare a setter function for it, of course, and with that you might add some validation etc.
Notice that the methods on the prototype object do not have access to the local variables of the constructor, yet they might use the privileged methods. Let's add one:
Foo.prototype.getFooBar = function() {
return this.getBar() + "bar"; // access the "getBar" function on "this" instance
}
// the inheritance is dynamic, so we can use it on our existing foo object
foo.getFooBar(); // "foobar" - concatenated the "bar" value with a custom suffix
So, you can combine both approaches. Notice that the privileged methods need more memory, as you create distinct function objects with different scope chains (yet the same code). If you are going to create incredibly huge amounts of instances, you should define methods only on the prototype.
It gets even a little more complicated when you are setting up inheritance from one "class" to another - basically you have to make the child prototype object inherit from the parent one, and apply the parent constructor on child instances to create the "private attributes". Have a look at Correct javascript inheritance, Private variables in inherited prototypes, Define Private field Members and Inheritance in JAVASCRIPT module pattern and How to implement inheritance in JS Revealing prototype pattern?

Explicitly saying this.foo means (as you've understood well) that you're interested about the property foo of the current object referenced by this. So if you use: this.foo = 'bar'; you're going to set the property foo of the current object referenced by this equals to bar.
The this keyword in JavaScript doesn't always mean the same thing like in C++. Here I can give you an example:
function Person(name) {
this.name = name;
console.log(this); //Developer {language: "js", name: "foo"} if called by Developer
}
function Developer(name, language) {
this.language = language;
Person.call(this, name);
}
var dev = new Developer('foo', 'js');
In the example above we're calling the function Person with the context of the function Developer so this is referencing to the object which will be created by Developer. As you might see from the console.log result this is comes from Developer. With the first argument of the method call we specify the context with which the function will be called.
If you don't use this simply the property you've created will be a local variable. As you might know JavaScript have functional scope so that's why the variable will be local, visible only for the function where it's declared (and of course all it's child functions which are declared inside the parent). Here is an example:
function foo() {
var bar = 'foobar';
this.getBar = function () {
return bar;
}
}
var f = new foo();
console.log(f.getBar()); //'foobar'
This is true when you use the var keyword. This means that you're defining bar as local variable if you forget var unfortunately bar will became global.
function foo() {
bar = 'foobar';
this.getBar = function () {
return bar;
}
}
var f = new foo();
console.log(window.bar); //'foobar'
Exactly the local scope can help you to achieve privacy and encapsulation which are one of the greatest benefits of OOP.
Real world example:
function ShoppingCart() {
var items = [];
this.getPrice = function () {
var total = 0;
for (var i = 0; i < items.length; i += 1) {
total += items[i].price;
}
return total;
}
this.addItem = function (item) {
items.push(item);
}
this.checkOut = function () {
var serializedItems = JSON.strigify(items);
//send request to the server...
}
}
var cart = new ShoppingCart();
cart.addItem({ price: 10, type: 'T-shirt' });
cart.addItem({ price: 20, type: 'Pants' });
console.log(cart.getPrice()); //30
One more example of the benefits of the JavaScript scope is the Module Pattern.
In Module Pattern you can simulate privacy using the local functional scope of JavaScript. With this approach you can have both private properties and methods. Here is an example:
var module = (function {
var privateProperty = 42;
function privateMethod() {
console.log('I\'m private');
}
return {
publicMethod: function () {
console.log('I\'m public!');
console.log('I\'ll call a private method!');
privateMethod();
},
publicProperty: 1.68,
getPrivateProperty: function () {
return privateProperty;
},
usePublicProperty: function () {
console.log('I\'ll get a public property...' + this.publicProperty);
}
}
}());
module.privateMethod(); //TypeError
module.publicProperty(); //1.68
module.usePublicProperty(); //I'll get a public property...1.68
module.getPrivateProperty(); //42
module.publicMethod();
/*
* I'm public!
* I'll call a private method!
* I'm private
*/
There's a little strange syntax with the parentless wrapping the anonymous functions but forget it for the moment (it's just executing the function after it's being initialized). The functionality can be saw from the example of usage but the benefits are connected mainly of providing a simple public interface which does not engages you with all implementation details. For more detailed explanation of the pattern you can see the link I've put above.
I hope that with this :-) information I helped you to understand few basic topics of JavaScript.

function Foo() {
this.bar = 0;
this.getBar = function () { return this.bar };
}
When you call the function above with the new keyword - like this...
var foo = new Foo();
... - a few things happen:
1) an object is created
2) the function is executed with the this keyword referencing that object.
3) that object is returned.
foo, then, becomes this object:
{
bar: 0,
getBar: function () { return this.bar; }
};
Why not, then, just do this:
var foo = {
bar: 0,
getBar: function () { return this.bar; }
};
You would, if it's just that one simple object.
But creating an object with a constructor (that's how it's called) gives us a big advantage in creating multiple of the "same" objects.
See, in javascript, all functions are created with a prototype property [an object], and all objects created with that function (by calling it with the new keyword) are linked to that prototype object. This is why it's so cool - you can store all common methods (and properties, if you wanted to) in the prototype object, and save a lot of memory. This is how it works:
function Foo( bar, bob ) {
this.bar = bar;
this.bob = bob;
}
Foo.prototype.calculate = function () {
// 'this' points not to the 'prototype' object
// as you could've expect, but to the objects
// created by calling Foo with the new keyword.
// This is what makes it work.
return this.bar - this.bob;
};
var foo1 = new Foo(9, 5);
var foo2 = new Foo(13, 3);
var result1 = foo1.calculate();
var result2 = foo2.calculate();
console.log(result1); //logs 4
console.log(result2); //logs 10
That's it!

To get closer to OOP in JavaScript, you might want to take a look into a Module design pattern (for instance, described here).
Based on the closure effect, this pattern allows emulating private properties in your objects.
With 'private' properties you can reference them directly by its identifier (i.e., no this keyword as in constructors).
But anyway, closures and design patterns in JS - an advanced topic. So, get familiar with basics (also explained in the book mentioned before).

In javascript this always refers to the owner object of the function. For example, if you define your function foo() in a page, then owner is the javascript object windows; or if you define the foo() on html element <body>, then the owner is the html element body; and likewise if you define the function onclick of element <a>, then the owner is the anchor.
In your case, you are assigning a property bar to the 'owner' object at the begining and trying to return the local variable bar.
Since you never defined any local varialbe bar, it is giving you as bar is undefined.
Ideally your code should have defined the variable as var bar; if you want to return the value zero.

this is like a public access modifier of objects(variables or functions), while var is the private access modifier
Example
var x = {};
x.hello = function(){
var k = 'Hello World';
this.m = 'Hello JavaScript';
}
var t = new x.hello();
console.log(t.k); //undefined
console.log(t.m); //Hello JavaScript

Setting C.prototype.constructor = C leads to StackOverflow

I have been learning about js inheritance and as a study project, I'm creating my own implementation of inheritance a base class extend method to create new classes. I use C.prototype.constructor = C as Stoyan Sefanov says to, however that leads to a stack overflow when I try to call the base class constructor.
The problem is that the second level of inheritance keeps on calling it's own constructor! If I remove that line, my inheritance seems to work fine.
jsfiddle sample.
Here is my implementation of the base class code.
(function(TestFramework, undefined) {
TestFramework.Class = function() {};
TestFramework.Class.extend = function(ctor) {
var base = this;
var derived = ctor;
//Duplicate static property access to derived
for (var property in base) {
if (base.hasOwnProperty(property)) derived[property] = base[property];
}
//Create lightweight intermediate constructor to avoid calling the base constructor
function lightweightCtor() { this.constructor = derived; };
//Setup prototype chain
lightweightCtor.prototype = base.prototype;
derived.prototype = new lightweightCtor();
derived.prototype._MyBase = lightweightCtor.prototype;
derived.prototype._MyBaseCtor = function() {
base.prototype.constructor.apply(this, arguments);
};
//Return derived class
return derived;
};
TestFramework.Class.prototype.ClassName = "TestFramework.Class";
})(window.TestFramework);

I spent a bit of time looking at the fiddle. I'm not entirely certain what you intend the code to do, but on line 23, you have:
base.prototype.constructor.apply(this, arguments);
which calls line 35..
this._MyBaseCtor();
.. which calls line 23, which calls line 35, etc.
Two suggestions (forgive me if you are well aware). Use the debugger statement when debugging - indispensable. And consider a library like Underscore.js if you want to use proven inheritance in a production environment.

Now that I understand the problem, the solution was pretty easy. I just had to store a reference to the original ctor before overwriting it and call that from within _MyBaseCtor. Here's the updated fiddle.
First, take out the constructor override inside of the lightweightCtor definition.
//Create lightweight intermediate constructor to avoid calling the base constructor
function lightweightCtor() {};
Then, add a new section to configure the constructor. Notice the check if base.__BaseCtor is configured and using the default base.prototype.constructor if it's not.
//Setup constructor references
derived.__BaseCtor = base.__BaseCtor || base.prototype.constructor;
derived.prototype.constructor = derived;
derived.prototype._MyBaseCtor = function() {
derived.__BaseCtor.apply(this, arguments);
};

class declared inside closure vs standard class without closure

Normally I use standard OOP approach based on prototype and my class looks like this
var std = function(){
this.log = function(msg){ console.log("want to be private. " + msg) };
};
std.prototype = {
logInfo: function(msg){
this.log(msg);
}
};
but in that case log is public method and anyone could use it. But I want to make it private, but still available in methods declared in prototype. For that we will need closures. Code will change to this
var closureStd = (function(){
var std = function(){};
var log = function(msg){ console.log("I'm really private, youhooo!" + msg) };
std.prototype = {
logInfo: function(msg){
log(msg);
}
};
return std;
})();
So my question: what is the difference between std and closureStd and what is the price I need to pay to be able to call private methods from prototype?

what is the difference between std and closureStd?
The std constructor creates a new method on every invocation while closureStd does not. You should've made it
function std(){}
std.prototype = {
log: function(msg){ console.log("want to be private. " + msg) },
logInfo: function(msg){ this.log(msg); }
};
And, of course (you already know) the log function in the closureStd is stored in a (private) variable while on the std instance it's accessible (and overwritable) from outside on each instance (or on their prototype). In the closure it's a variable lookup in the scope chain (which can assumed static), while for the method it's a property lookup on an object (and its prototype chain), which might be dynamic but is equally optimized in modern engines.
what is the price I need to pay to be able to call private methods from prototype?
None. The module pattern is common and cheap, variable lookups in a static chain are very fast. I'd rather worry about memory since you're creating so many method instances in the constructor approach.

I also made some tests to measure performance (result's will be in console) and I find that putting class in closure demonstrate better performance compare to put methods in constructor. You also have inheritance options. So for now I don't see disadvantages and will always use class inside closure when I'll need private methods.

Note that the module pattern provided by the link Bondye provided does not hold private instance properties. It works great for function properties since the function would not change for each instance but works a little unpredictable for value properties as the following code demonstrates:
var module = (function () {
// private variables and functions
var foo = 'bar';
// constructor
var module = function (name) {
// instance variables
this.name=name;
};
// prototype
module.prototype = {
constructor: module,
something: function () {
// notice we're not using this.foo
console.log("foo in "+this.name+" is:",foo);
foo="new value";
}
};
// return module
return module;
})();
var m1 = new module("m1");
var m2 = new module("m2");
m1.something();// foo in m1 is: bar
m1.something();// foo in m1 is: new value
m2.something();// foo in m2 is: new value
As you can see in the last line of code both the m1 and m2 instance share a private variable called foo (all instances will point to the same value).
What I could make out from the other link that Bondye posted is that it's hard to simulate privateness in JavaScript and you could consider using a naming convention to indicate properties are private. You can use something like google closure compiler and annotate your JS code to indicate privates; but using closure compiler has it's own disadvantages (used libraries cannot be compiled unless Closure Compiler compatible and code has to be in certain format to be compiled in advanced mode).
Another option is to throw out prototype altogether (at least for everything using the private properties) and put everything in the constructor function's body (or use a function that returns an object).
// function returning an object
function makeObj(name){
// private vars:
var foo = "bar";
return {
name:name,
something:function(){
console.log("foo in "+this.name+" is:",foo);
foo="new value";
}
}
}
var m1=makeObj("m1");
var m2=makeObj("m2");
m1.something();// foo in m1 is: bar
m1.something();// foo in m1 is: new value
m2.something();// foo in m2 is: bar
// constructor with everything in the constructor's body:
function Obj(name){
// private vars:
var foo = "bar";
this.name=name;
this.something=function(){
console.log("foo in "+this.name+" is:",foo);
foo="new value";
}
}
Obj.prototype.someOtherFunction=function(){
// anything here can't access the "private" variables
}
var m1=new Obj("m1");
var m2=new Obj("m2");
m1.something();// foo in m1 is: bar
m1.something();// foo in m1 is: new value
m2.something();// foo in m2 is: bar
One more problem you can run into with using private instance values is that they are only accessible in the instance. When you want to clone an object and define a clone function in your object to create a new instance you have to write public accessor functions to set the private values because you can't set them directly as in Java private fields.
More info on using constructor functions here: Prototypical inheritance - writing up

Performance disadvantages of using this javascript pattern?

I am trying to duplicate private prototype methods in javascript and found this bit of code, but I do not fully understand how it implements itself.
The code is...
var Foo = function () {};
Foo.prototype = (function () {
// Private attributes
var somePrivateAttribute = 'Hello world';
// Private methods
function somePrivateMethod(val) {
alert(val);
}
// Public attributes and methods
return {
somePublicMethod: function () {
somePrivateMethod(somePrivateAttribute);
}
};
})();
What I do not understand is when this object is initiated new Foo() does that create a new object for the prototype every time as it is in a self executing function? Could anyone please explain the benefits and disadvantages of using this for a project of mine.
How would this type of pattern work for objects that could have 500 instances or just 1. I am trying to understand and would greatly appreciate if anyone could enlighten me?
Is there any performance benefits to using this method?

What I do not understand is when this object is initiated new Foo() does that create a new object for the prototype every time as it is in a self executing function?
No. That's the point of prototypes, they are not duplicated - every of your Foo instances will inherit from the same Foo.prototype object.
Could anyone please explain the benefits and disadvantages of using this for a project of mine.
It looks like you're having a little misunderstanding, regarding the naming: Those "private" things are no "attributes" or "methods", as they have absolutely nothing to do with instance objects. They are just local variables which are only accessible from the functions you assign to the prototype object.
You might want to read How do JavaScript closures work? and their use in IIFEs.
How would this type of pattern work for objects that could have 500 instances or just 1.
It's perfectly fine. However, using the constructor pattern for just 1 instance might be a little odd - singletons can be defined in a simpler way.
If you want to read more on that pattern, search for revealing prototype pattern - it's the revealing module pattern applied to create prototype objects.

I haven't seen that pattern before, using a module (that's what it's called) for the prototype... but here's what I'd recommend; it's similar but the module encloses everything:
var Foo = (function FooClass() {
var privateVar = 'Hello world';
function privateFunc() {
...
}
function Foo() {}
Foo.prototype = {
publicMethod: function() {
...
}
};
return Foo;
}());
var foo = new Foo();
What I do not understand is when this object is initiated new Foo()
does that create a new object for the prototype every time as it is in
a self executing function?
The self executing function runs once, returns the object, and it won't run again; it keeps a reference to the variables via closure.

What I do not understand is when this object is initiated new Foo() does that create a new object for the prototype every time as it is in a self executing function?
No, the assignment to Foo's prototype only happens once. Nothing wrong with it at all, just a little unconventional.
You could also write it like this (also unconventional, but accomplishes the same thing):
var Foo = function () {};
Foo.prototype = new function() {
// Private attributes
var somePrivateAttribute = 'Hello world';
// Private methods
function somePrivateMethod(val) {
alert(val);
}
// Public attributes and methods
this.constructor = Foo;
this.somePublicMethod = function () {
somePrivateMethod(somePrivateAttribute);
}
};
As Bergi pointed out, this adds an extra object to the prototype chain; if you want to avoid that, you can write it like this instead:
var Foo = function () {};
(function() {
// Private attributes
var somePrivateAttribute = 'Hello world';
// Private methods
function somePrivateMethod(val) {
alert(val);
}
// Public attributes and methods
this.somePublicMethod = function () {
somePrivateMethod(somePrivateAttribute);
}
}).call(Foo.prototype)
By modifying the prototype instead of replacing it, the constructor property also stays intact.

Does jQuery or JavaScript have the concept of classes and objects?

I found the following code somewhere, but I am not understanding the code properly.
ArticleVote.submitVote('no');return false;
Is ArticleVote a class and submitVote() a function of that class?
Or what does the above code mean? And is there any concept of classes and objects in jQuery or in traditional JavaScript? How to create them? Please share some reference links or code.

Everything is an object in JavaScript
As opposed to other purportedly pure OOP languages. Functions are objects too, but they may just as well be constructor of objects.
var ObjectCreator = function () {
};
The above is a function which if called appropriately, creates an object. Called appropriately means that you have to use the new operator:
var obj = new ObjectCreator;
So while JavaScript does not have classes per se, has means to emulate that behavior. For example:
class Foo {
public void bar() {}
}
Foo foo = new Foo();
is equivalent to the following JS code:
var Foo = function () {
// constructor
};
Foo.prototype.bar = function () {}
var foo = new Foo;
Inheritance is different
The real difference comes when you want to use inheritance, which is a different type of inheritance (prototypal). So, given two pseudo-classes Foo and Bar, if we want Bar to extend from Foo, we would have to write:
var Foo = function () {};
var Bar = function () {};
Bar.prototype = new Foo; // this is the inheritance phase
var bar = new Bar;
alert(bar instanceof Foo);
Object literals
While constructor functions are useful, there are times when we only need only one instance of that object. Writing a constructor function and then populate its prototype with properties and methods is somehow tedious. So JavaScript has object literals, which are some kind of hash tables, only that they're self-conscious. By self-conscious I mean that they know about the this keyword. Object literals are a great way to implement the Singleton pattern.
var john = {
age : 24,
isAdult : function () {
return this.age > 17;
}
};
The above, using a constructor function would be equivalent to the following:
var Person = function (age) {
this.age = age;
};
Person.prototype.isAdult = function () {
return this.age > 17;
};
var john = new Person(24);
What about that prototype thingy
As many have said, in JavaScript objects inherit from objects. This thing has useful aspects, one of which may be called, parasitic inheritance (if I remember correctly the context in which Douglas Crockford mentioned this). Anyway, this prototype concept is associated with the concept of prototype chain which is similar to the parent -> child chain in classical OO languages. So, the inheritance stuff. If a bar method is called on a foo object, but that object does not have a bar method, a member lookup phase is started:
var Baz = function () {};
Baz.prototype.bar = function () {
alert(1);
};
var Foo = function () {};
Foo.prototype = new Baz;
var foo = new Foo;
/*
* Does foo.bar exist?
* - yes. Then execute it
* - no
* Does the prototype object of the constructor function have a bar
* property?
* - yes. Then execute it
* - no
* Is there a constructor function for the prototype object of
* the initial construct function? (in our case this is Baz)
* - yes. Then it must have a prototype. Lookup a bar
* member in that prototype object.
* - no. OK, we're giving up. Throw an error.
*/
foo.bar();
Hold on, you said something about parasitic inheritance
There is a key difference between classical OO inheritance and prototype-based inheritance. When objects inherit from objects, they also inherit state. Take this example:
var Person = function (smart) {
this.smart = smart;
};
var Adult = function (age) {
this.age = age;
};
Adult.prototype = new Person(true);
var john = new Adult(24);
alert(john.smart);
We could say that john is a parasite of an anonymous Person, because it merciless sucks the person intelligence. Also, given the above definition, all future adults will be smart, which unfortunately is not always true. But that doesn't mean object inheritance is a bad thing. Is just a tool, like anything else. We must use it as we see fit.
In classical OO inheritance we can't do the above. We could emulate it using static fields though. But that would make all instances of that class having the same value for that field.

Javascript supports objects but not classes - it uses a prototype-based object system.

JavaScript supports object-oriented development
Object-oriented JavaScript

Certainly JS has objects and classes, but it's not exactly a conventional approach.
It's rather a broad question, but there's three main things you want to know about objects and classes in JS:
1). Everything is an object - this famously includes JS's first class functions
2). There are object literals
var myObject = { "foo": 123, "bar": [4,5,6] };
3). Inheritance is prototype based, so creating classes is more a matter of form than function. To get the effect of a class you'd write something like:
function myClass(foo)
{
this.foo = foo;
}
myClass.prototype.myFooMethod = function() {alert(this.foo);}
var myInstance = new myClass(123);
myinstance.myFooMethod(); // alerts 123
For your example it's likely that ArticleVote is an object instance and probably not conceptually a class, and submitVote would be a method of the object. can't tell for sure though, it could be what you'd call a static method in another language.

Yes, JavaScript has impressive support for Object Oriented programming, Objects and functions. In fact, I'm surprised that you have to ask this question! There are a wealth of resources online such as:
http://mckoss.com/jscript/object.htm
http://www.webreference.com/js/column79/
http://www.javascriptkit.com/javatutors/oopjs.shtml
More resources:
http://www.google.com/search?q=object+oriented+programming+javascript
JavaScript frameworks such as jQuery and Prototype could not have been built without this support in JavaScript engines.

You can achieve the above through Javascript, nothing to do with jQuery.
var ArticleVote= {};
ArticleVote.submitVote = function(voteResult) {
console.log(voteResult);
}
function Vote(){
ArticleVote.submitVote('no');
return false;
}

You can use the JavaScript function as class.
ClassUtil = function(param){
privateFunction = function(param){
// Do some thing
return valueParam;
}
this.publicFunction = function(){
var val1 = function1();
if (val1){
return true;
} else{
return false;
}
}
}
function getClass(){
var classUtil = new ClassUtil();
alert(classUtil.publicFunction());
}
There is one public and one private function. You can call public function from out side using object of the class.