Explanation/Reference:
Note:

* Here there is a basic example:
// our constructor
function Person(name, age){
this.name = name;
this.age = age;
};
// prototype assignment
Person.prototype = (function(){
// we have a scope for private stuff
// created once and not for every instance
function toString(){
return this.name + " is " + this.age;
};
// create the prototype and return them
return {
// never forget the constructor ...
constructor:Person,
// "magic" toString method
toString:function(){
// call private toString method
return toString.call(this);
}
};
})();
* Example:
You can simulate private methods like this:
function Restaurant() {
}
Restaurant.prototype = (function() {
var private_stuff = function() {
// Private code here
};
return {
constructor:Restaurant,
use_restroom:function() {
private_stuff();
}
};
})();
var r = new Restaurant();
// This will work:
r.use_restroom();
// This will cause an error:
r.private_stuff();