Backbone.js Collection with filters

FilteredCollection.js

RailsCollection = Backbone.Collection.extend({
  initialize: function() {
    _.bindAll(this, 'url');
  },

  url: function() {
    var base = this.baseUrl || this.model.prototype.baseUrl;

    if(!this.params) {
      return base;
    } else {
      return base + '?' + $.param(this.params);
    }
  }
});

// Should also be able to do this by passing the 'data' option to the collection's 
// fetch method.

RailsCollection = Backbone.Collection.extend({

});

coll = new RailsCollection();
var year_and_month = '2011-10';

coll.fetch({data: {date: year_and_month}});
// GET request to url?date=2001-10