Js object-oriented programming, four methods of defining classes

Method 1:

/* Anim class. */var Anim = function() {  ...};Anim.prototype.start = function() {  ...};Anim.prototype.stop = function() {  ...};/* Usage. */var myAnim = new Anim();myAnim.start();...myAnim.stop();

Method 2:

/* Anim class, with a slightly different syntax for declaring methods. */var Anim = function() {   ...};Anim.prototype = {  start: function() {    ...  },  stop: function() {    ...  }};

Method 3:

/* Add a method to the Function class that can be used to declare methods. */Function.prototype.method = function(name, fn) {  this.prototype[name] = fn;};/* Anim class, with methods created using a convenience method. */var Anim = function() {   ...};Anim.method('start', function() {  ...});Anim.method('stop', function() {  ...});

Method 4:

/* This version allows the calls to be chained. */Function.prototype.method = function(name, fn) {    this.prototype[name] = fn;    return this;};/* Anim class, with methods created using a convenience method and chaining. */var Anim = function() {   ...};Anim.  method('start', function() {    ...  }).  method('stop', function() {    ...  });