Easy example to show how to extend an existing Backbone class inheriting its properties to the new children classes

Backbone_Class_Inheritance.js

/*
*
* Parent class containing some methods and properties that must be inherited  
*
*/
var ParentClass = Backbone.Model.extend({
  initialize: function() {
    this.set('name','Dear');
  },
  say_hello: function ( ) {
    // property set only on the child
    console.log(this.get('greeting'));
  }
});
/*
*
* Child class extending the ParentClass 
*
*/
var ChildClass = ParentClass.extend({
  initialize: function () {
    this.constructor.__super__.initialize.apply(this);
    this.set('greeting','Hello!');
    // inherited method
    this.say_hello();
    // inherited property
    console.log(this.get('name'));
    // property set later once the class gets instanced
    console.log(this.get('surname'));
  }
});

new ChildClass({
    surname:'Friends'
});

Check it out the demo http://jsfiddle.net/gianlucaguarini/RuQxL/