Access private attribute Javascript OOP

Question

I want to know how to create a private attribute in a Javascript class. I tried this:

function Class1(selector)
{
    //calling the constructor
    Constructor();

    //private attribute
    var $container = null;

    function Constructor()
    {
        $container = $(selector);

        //Shows that container is an object
        alert($container);
    }

    function Foo()
    {
         //Shows that container is null
         alert($container);
    }

    result {
        Foo : Foo
    };
}

I supposed that in "Constructor" it creates a new variable $container and assign the object to it. I want to know how I am suposed to assign the value to the attribute $container of the object and not the local variable in the function Constructor.

Answer 1

this is because you first call Constructor() and after that you assign null to $container

If you switch that around you will get the desired result:

http://jsfiddle.net/R8RG5/

Answer 2

function Class1(selector) {

    var container = null; //private attribute
    constructor(); //calling the constructor

    function constructor() {
        container = $(selector);
        console.log($container); //Shows that container is an object
    }

    function foo() {
         console.log(container); //Shows that container is null
    }

    result { Foo : foo };
}

such as red-X already told: you have to execute the constructor after initialization of the container variable.

In my example: is is a better practice to use console.log for debugging..