Example of very simple JavaScript inheritance using JS core features only, following the style used in the WebKit Web Inspector.

inheritance.js

function Bar(someParam)
{
    // Call the superclass's constructor
    Foo.call(this, someParam);
    // Bar-specific initialization follows…
    this._property = null;
}

// Some constants.
Bar.Constants = {
    Foo: "foo",
    Bar: "bar",
    Baz: "baz"
};

Bar.staticMethod = function()
{
    // A static method
};

Bar.prototype = {
    constructor: Bar,
    __proto__: Foo.prototype,
    
    // Public
    
    get someProperty()
    {
        // a property accessor for .someProperty
        return this._property;
    },

    set someProperty(x)
    {
        // a property setter for .someProperty
        this._property = x;
    },
    
    doSomething: function(someParam)
    {
        // a public method, where you can easily call the superclass's implementation
        return Foo.prototype.doSomething.call(this, someParam);
    },
    
    // Protected
    
    handleEvent: function(event)
    {
        // a protected method, for instance an implementation of the DOM EventListener interface,
        // can also be used for implementations of delegation protocols
    },
    
    // Private
    
    _doSomethingPrivate: function()
    {
        // a private method
    }
};