Why use public methods in JavaScript objects? [duplicate]

Question

I'm part of a small study group at work that's trying to get a better grasp on what makes JavaScript tick. In our recent discussions about objects, we've learned that an object's public methods are recreated each time an object is instantiated, while methods assigned to the object's prototype are only created once and inherited by all instances. From what I understand, both public methods and those assigned to the prototype are publicly accessible.

The question I have, then, is why bother creating public methods at all if adding to the prototype is apparently more efficient? What benefit does the public method provide that the prototype doesn't?

Answer 1

Answering this specifically:

What benefit does the public method provide that the prototype doesn't?

A method added within the constructor has access to private information, eg:

function Student() {     var name = 'Bob';     this.GetName = function() {         return name;     } }  Student.prototype.SomeOtherPublicMethod = function() {     //no access to name }