Sample implementation of JavaScript module pattern to explain private and public members.

module_pattern.js

var Talkative = ( function( w, $ ) {

    // this object is used to store private variables and methods across multiple instantiations
    var privates = {
        "secret" : 'Not to share'
    };

    // A shared private method
    privates.talk = function (msg) {
        w.alert('whisper : ' + msg);
    };

    function Watchlist() {

        // A public method
        this.bigTalk = function bigTalk() {
            w.alert( 'Big Talk!' );
        };

        // Public method using private variable
        this.accessSecret = function accessSecret() {
            w.alert( privates.secret );
        };

        // Public method using private function
        this.accessPrivetTalk = function accessPrivetTalk() {
            privates.talk('Private Talk');
        };

    }

    return Watchlist;

} )( window, $);

var whoever = new Talkative();
whoever.bigTalk();
whoever.accessSecret();
whoever.accessPrivetTalk();