JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://documentcloud.github.com/underscore/underscore.js"></script>
<script src="http://documentcloud.github.com/backbone/backbone.js"></script>

JavaScript

// http://forrst.com/posts/Backbone_js_super_function-4co
Backbone.Model.prototype._super = function(method){
  return this.constructor.__super__[method].apply(this, _.rest(arguments));
}

var animal = Backbone.Model.extend({
  defaults: {
    id:0,
    name:'this is animal name'
  },
  sound: function() { return '(incoherent grunting)'; },
  talk: function() { alert(this.sound()); }
});

var yeti = animal.extend({
  defaults: _.extend({}, animal.defaults, {
    cost:500
  }),
  test: function() {
    alert('cost : ' + this.get('name'));
  }
});
(new yeti).test();