blog.js

var Person = (function() {
    var ctor = function(name) {
        var _name = name;
        this.get_name = function() { return _name; } // Wrap the private variable with a getter
    };

    ctor.prototype.sayHello = function () {
        console.log("Hello " + this.get_name());
    }

    return ctor;
})();

var sue = new Person('sue');
var bill = new Person('bill');
sue.sayHello();     // prints Hello sue
bill.sayHello();    // prints Hello bill