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<body>

  <div id="sidebar" class="interface">

    <a class="toc_title" href="#">
      Backbone.js <span class="version">(0.9.2)</span>
    </a>
    <ul class="toc_section">
      <li>&raquo; <a href="http://github.com/documentcloud/backbone">GitHub Repository</a></li>
      <li>&raquo; <a href="docs/backbone.html">Annotated Source</a></li>
    </ul>

    <a class="toc_title" href="#introduction">
      Introduction
    </a>

    <a class="toc_title" href="#upgrading">
      Upgrading
    </a>

    <a class="toc_title" href="#Events">
      Events
    </a>
    <ul class="toc_section">
      <li>– <a href="#Events-on">on</a></li>
      <li>– <a href="#Events-off">off</a></li>
      <li>– <a href="#Events-trigger">trigger</a></li>
      <li>- <a href="#Events-catalog"><b>Catalog of Built-in Events</b></a></li>
    </ul>

    <a class="toc_title" href="#Model">
      Model
    </a>
    <ul class="toc_section">
      <li>– <a href="#Model-extend">extend</a></li>
      <li>– <a href="#Model-constructor">constructor / initialize</a></li>
      <li>– <a href="#Model-get">get</a></li>
      <li>– <a href="#Model-set">set</a></li>
      <li>– <a href="#Model-escape">escape</a></li>
      <li>– <a href="#Model-has">has</a></li>
      <li>– <a href="#Model-unset">unset</a></li>
      <li>– <a href="#Model-clear">clear</a></li>
      <li>– <a href="#Model-id">id</a></li>
      <li>– <a href="#Model-idAttribute">idAttribute</a></li>
      <li>– <a href="#Model-cid">cid</a></li>
      <li>– <a href="#Model-attributes">attributes</a></li>
      <li>– <a href="#Model-changed">changed</a></li>
      <li>– <a href="#Model-defaults">defaults</a></li>
      <li>– <a href="#Model-toJSON">toJSON</a></li>
      <li>– <a href="#Model-sync">sync</a></li>
      <li>– <a href="#Model-fetch">fetch</a></li>
      <li>– <a href="#Model-save">save</a></li>
      <li>– <a href="#Model-destroy">destroy</a></li>
      <li>– <a href="#Model-validate">validate</a></li>
      <li>– <a href="#Model-isValid">isValid</a></li>
      <li>– <a href="#Model-url">url</a></li>
      <li>– <a href="#Model-urlRoot">urlRoot</a></li>
      <li>– <a href="#Model-parse">parse</a></li>
      <li>– <a href="#Model-clone">clone</a></li>
      <li>– <a href="#Model-isNew">isNew</a></li>
      <li>– <a href="#Model-change">change</a></li>
      <li>– <a href="#Model-hasChanged">hasChanged</a></li>
      <li>– <a href="#Model-changedAttributes">changedAttributes</a></li>
      <li>– <a href="#Model-previous">previous</a></li>
      <li>– <a href="#Model-previousAttributes">previousAttributes</a></li>
    </ul>

    <a class="toc_title" href="#Collection">
      Collection
    </a>
    <ul class="toc_section">
      <li>– <a href="#Collection-extend">extend</a></li>
      <li>– <a href="#Collection-model">model</a></li>
      <li>– <a href="#Collection-constructor">constructor / initialize</a></li>
      <li>– <a href="#Collection-models">models</a></li>
      <li>– <a href="#Collection-toJSON">toJSON</a></li>
      <li>– <a href="#Collection-sync">sync</a></li>
      <li>– <a href="#Collection-Underscore-Methods"><b>Underscore Methods (28)</b></a></li>
      <li>– <a href="#Collection-add">add</a></li>
      <li>– <a href="#Collection-remove">remove</a></li>
      <li>– <a href="#Collection-get">get</a></li>
      <li>– <a href="#Collection-getByCid">getByCid</a></li>
      <li>– <a href="#Collection-at">at</a></li>
      <li>– <a href="#Collection-push">push</a></li>
      <li>– <a href="#Collection-pop">pop</a></li>
      <li>– <a href="#Collection-unshift">unshift</a></li>
      <li>– <a href="#Collection-shift">shift</a></li>
      <li>– <a href="#Collection-length">length</a></li>
      <li>– <a href="#Collection-comparator">comparator</a></li>
      <li>– <a href="#Collection-sort">sort</a></li>
      <li>– <a href="#Collection-pluck">pluck</a></li>
      <li>– <a href="#Collection-where">where</a></li>
      <li>– <a href="#Collection-url">url</a></li>
      <li>– <a href="#Collection-parse">parse</a></li>
      <li>– <a href="#Collection-clone">clone</a></li>
      <li>– <a href="#Collection-fetch">fetch</a></li>
      <li>– <a href="#Collection-reset">reset</a></li>
      <li>– <a href="#Collection-create">create</a></li>
    </ul>

    <a class="toc_title" href="#Router">
      Router
    </a>
    <ul class="toc_section">
      <li>– <a href="#Router-extend">extend</a></li>
      <li>– <a href="#Router-routes">routes</a></li>
      <li>– <a href="#Router-constructor">constructor / initialize</a></li>
      <li>– <a href="#Router-route">route</a></li>
      <li>– <a href="#Router-navigate">navigate</a></li>
    </ul>

    <a class="toc_title" href="#History">
      History
    </a>
    <ul class="toc_section">
      <li>– <a href="#History-start">start</a></li>
    </ul>

    <a class="toc_title" href="#Sync">
      Sync
    </a>
    <ul class="toc_section">
      <li>– <a href="#Sync">Backbone.sync</a></li>
      <li>– <a href="#Sync-ajax">Backbone.ajax</a></li>
      <li>– <a href="#Sync-emulateHTTP">Backbone.emulateHTTP</a></li>
      <li>– <a href="#Sync-emulateJSON">Backbone.emulateJSON</a></li>
    </ul>

    <a class="toc_title" href="#View">
      View
    </a>
    <ul class="toc_section">
      <li>– <a href="#View-extend">extend</a></li>
      <li>– <a href="#View-constructor">constructor / initialize</a></li>
      <li>– <a href="#View-el">el</a></li>
      <li>– <a href="#View-$el">$el</a></li>
      <li>– <a href="#View-setElement">setElement</a></li>
      <li>– <a href="#View-attributes">attributes</a></li>
      <li>– <a href="#View-dollar">$ (jQuery or Zepto)</a></li>
      <li>– <a href="#View-render">render</a></li>
      <li>– <a href="#View-remove">remove</a></li>
      <li>– <a href="#View-dispose">dispose</a></li>
      <li>– <a href="#View-make">make</a></li>
      <li>– <a href="#View-delegateEvents">delegateEvents</a></li>
      <li>– <a href="#View-undelegateEvents">undelegateEvents</a></li>
    </ul>

    <a class="toc_title" href="#Utility">
      Utility
    </a>
    <ul class="toc_section">
      <li>– <a href="#Utility-Backbone-noConflict">Backbone.noConflict</a></li>
      <li>– <a href="#Utility-Backbone-$">Backbone.$</a></li>
    </ul>

    <a class="toc_title" href="#examples">
      Examples
    </a>
    <ul class="toc_section">
      <li>– <a href="#examples-todos">Todos</a></li>
      <li>– <a href="#examples-documentcloud">DocumentCloud</a></li>
      <li>– <a href="#examples-usa-today">USA Today</a></li>
      <li>– <a href="#examples-rdio">Rdio</a></li>
      <li>– <a href="#examples-linkedin">LinkedIn Mobile</a></li>
      <li>– <a href="#examples-hulu">Hulu</a></li>
      <li>– <a href="#examples-flow">Flow</a></li>
      <li>– <a href="#examples-gilt">Gilt Groupe</a></li>
      <li>– <a href="#examples-newsblur">NewsBlur</a></li>
      <li>– <a href="#examples-wordpress">WordPress.com</a></li>
      <li>– <a href="#examples-foursquare">Foursquare</a></li>
      <li>– <a href="#examples-bitbucket">Bitbucket</a></li>
      <li>– <a href="#examples-disqus">Disqus</a></li>
      <li>– <a href="#examples-khan-academy">Khan Academy</a></li>
      <li>– <a href="#examples-do">Do</a></li>
      <li>– <a href="#examples-irccloud">IRCCloud</a></li>
      <li>– <a href="#examples-pitchfork">Pitchfork</a></li>
      <li>– <a href="#examples-spin">Spin</a></li>
      <li>– <a href="#examples-walmart">Walmart Mobile</a></li>
      <li>– <a href="#examples-groupon">Groupon Now!</a></li>
      <li>– <a href="#examples-basecamp">Basecamp</a></li>
      <li>– <a href="#examples-slavery-footprint">Slavery Footprint</a></li>
      <li>– <a href="#examples-stripe">Stripe</a></li>
      <li>– <a href="#examples-airbnb">Airbnb</a></li>
      <li>– <a href="#examples-diaspora">Diaspora</a></li>
      <li>– <a href="#examples-soundcloud">SoundCloud Mobile</a></li>
      <li>- <a href="#examples-artsy">Art.sy</a></li>
      <li>– <a href="#examples-pandora">Pandora</a></li>
      <li>– <a href="#examples-inkling">Inkling</a></li>
      <li>– <a href="#examples-code-school">Code School</a></li>
      <li>– <a href="#examples-cloudapp">CloudApp</a></li>
      <li>– <a href="#examples-seatgeek">SeatGeek</a></li>
      <li>– <a href="#examples-easel">Easel</a></li>
      <li>– <a href="#examples-prose">Prose</a></li>
      <li>– <a href="#examples-scrollkit">scroll kit</a></li>
      <li>- <a href="#examples-jolicloud">Jolicloud</a></li>
      <li>– <a href="#examples-battlefield">Battlefield Play4Free</a></li>
      <li>– <a href="#examples-syllabus">Syllabus</a></li>
      <li>– <a href="#examples-salon">Salon.io</a></li>
      <li>– <a href="#examples-tilemill">TileMill</a></li>
      <li>– <a href="#examples-blossom">Blossom</a></li>
      <li>– <a href="#examples-decide">Decide</a></li>
      <li>– <a href="#examples-trello">Trello</a></li>
      <li>– <a href="#examples-tzigla">Tzigla</a></li>
    </ul>

    <a class="toc_title" href="#faq">
      F.A.Q.
    </a>
    <ul class="toc_section">
      <li>– <a href="#FAQ-why-backbone">Why Backbone?</a></li>
      <li>– <a href="#FAQ-tim-toady">More Than One Way To Do It</a></li>
      <li>– <a href="#FAQ-nested">Nested Models &amp; Collections</a></li>
      <li>– <a href="#FAQ-bootstrap">Loading Bootstrapped Models</a></li>
      <li>– <a href="#FAQ-extending">Extending Backbone</a></li>
      <li>– <a href="#FAQ-mvc">Traditional MVC</a></li>
      <li>– <a href="#FAQ-this">Binding "this"</a></li>
      <li>– <a href="#FAQ-rails">Working with Rails</a></li>
    </ul>

    <a class="toc_title" href="#changelog">
      Change Log
    </a>

  </div>

  <div class="container">

    <p>
      <img id="logo" src="docs/images/backbone.png" alt="Backbone.js" />
    </p>

    <p>
      Backbone.js gives structure to web applications
      by providing <b>models</b> with key-value binding and custom events,
      <b>collections</b> with a rich API of enumerable functions,
      <b>views</b> with declarative event handling, and connects it all to your
      existing API over a RESTful JSON interface.
    </p>

    <p>
      The project is <a href="http://github.com/documentcloud/backbone/">hosted on GitHub</a>,
      and the <a href="docs/backbone.html">annotated source code</a> is available,
      as well as an online <a href="test/">test suite</a>,
      an <a href="examples/todos/index.html">example application</a>,
      a <a href="https://github.com/documentcloud/backbone/wiki/Tutorials%2C-blog-posts-and-example-sites">list of tutorials</a>
      and a <a href="#examples">long list of real-world projects</a> that use Backbone.
      Backbone is available for use under the <a href="http://github.com/documentcloud/backbone/blob/master/LICENSE">MIT software license</a>.
    </p>

    <p>
      You can report bugs and discuss features on the
      <a href="http://github.com/documentcloud/backbone/issues">GitHub issues page</a>,
      on Freenode IRC in the <tt>#documentcloud</tt> channel, post questions to the
      <a href="https://groups.google.com/forum/#!forum/backbonejs">Google Group</a>,
      add pages to the <a href="https://github.com/documentcloud/backbone/wiki">wiki</a>
      or send tweets to <a href="http://twitter.com/documentcloud">@documentcloud</a>.
    </p>

    <p>
      <i>
        Backbone is an open-source component of
        <a href="http://documentcloud.org/">DocumentCloud</a>.
      </i>
    </p>

    <h2 id="downloads">
      Downloads &amp; Dependencies
      <span style="padding-left: 7px; font-size:11px; font-weight: normal;" class="interface">(Right-click, and use "Save As")</span>
    </h2>

    <table>
      <tr>
        <td><a class="punch" href="backbone.js">Development Version (0.9.2)</a></td>
        <td class="text"><i>52kb, Full source, lots of comments</i></td>
      </tr>
      <tr>
        <td><a class="punch" href="backbone-min.js">Production Version (0.9.2)</a></td>
        <td class="text"><i>5.6kb, Packed and gzipped</i></td>
      </tr>
      <tr>
        <td><a class="punch" href="https://raw.github.com/documentcloud/backbone/master/backbone.js">Edge Version (master)</a></td>
        <td>
          <i>Unreleased, use at your own risk</i>
          <a href="https://travis-ci.org/documentcloud/backbone">
            <img width="89" height="13" src="https://travis-ci.org/documentcloud/backbone.png" />
          </a>
        </td>
      </tr>
    </table>

    <p>
      Backbone's only hard dependency is either
      <a href="http://underscorejs.org/">Underscore.js</a> <small>( > 1.3.3)</small> or
      <a href="http://lodash.com">Lo-Dash</a>.
      For RESTful persistence, history support via <a href="#Router">Backbone.Router</a>
      and DOM manipulation with <a href="#View">Backbone.View</a>, include
      <a href="https://github.com/douglascrockford/JSON-js">json2.js</a>, and either
      <a href="http://jquery.com">jQuery</a> <small>( > 1.4.2)</small> or
      <a href="http://zeptojs.com/">Zepto</a>.
    </p>

    <h2 id="introduction">Introduction</h2>

    <p>
      When working on a web application that involves a lot of JavaScript, one
      of the first things you learn is to stop tying your data to the DOM. It's all
      too easy to create JavaScript applications that end up as tangled piles of
      jQuery selectors and callbacks, all trying frantically to keep data in
      sync between the HTML UI, your JavaScript logic, and the database on your
      server. For rich client-side applications, a more structured approach
      is often helpful.
    </p>

    <p>
      With Backbone, you represent your data as
      <a href="#Model">Models</a>, which can be created, validated, destroyed,
      and saved to the server. Whenever a UI action causes an attribute of
      a model to change, the model triggers a <i>"change"</i> event; all
      the <a href="#View">Views</a> that display the model's state can be notified of the
      change, so that they are able to respond accordingly, re-rendering themselves with
      the new information. In a finished Backbone app, you don't have to write the glue
      code that looks into the DOM to find an element with a specific <i>id</i>,
      and update the HTML manually
      &mdash; when the model changes, the views simply update themselves.
    </p>

    <p>
      If you're new here, and aren't yet quite sure what Backbone is for, start by
      browsing the <a href="#examples">list of Backbone-based projects</a>.
    </p>

    <p>
      Many of the examples that follow are runnable. Click the <i>play</i> button
      to execute them.
    </p>

    <h2 id="upgrading">Upgrading to 0.9</h2>

    <p>
      Backbone's <b>0.9</b> series should be considered as a release candidate
      for an upcoming <b>1.0</b>. Some APIs have changed, and while there is a
      <a href="#changelog">change log</a> available, and many new features to
      take advantage of, there are a few specific changes where you'll need
      to take care:
    </p>

    <ul>
      <li>
        If you've ever manually set <tt>this.el</tt> in a Backbone View to be a
        particular DOM element, you'll want to use
        <a href="#View-setElement">setElement</a> instead.
      </li>
      <li>
        Creating and destroying models is now optimistic. Pass <tt>{wait: true}</tt>
        if you need the previous behavior of waiting for the server to acknowledge
        success. You can now also pass <tt>{wait: true}</tt> to <a href="#Model-save">save</a> calls.
      </li>
      <li>
        If you have been writing a fair amount of <tt>$(view.el)</tt>, there's now
        a cached reference for that jQuery object: <a href="#View-$el">$el</a>.
      </li>
      <li>
        If you're upgrading, make sure you also upgrade your version of Underscore.js
        to the latest &mdash; 1.3.1 or greater.
      </li>
      <li>
        <tt>model.set</tt> will no longer trigger change events when setting a value
        with <tt>{silent: true}</tt> then setting it back to its original value.
        Similarly, after changing an attribute silently, that <tt>change:attribute</tt>
        event <i>will</i> fire during the next change.
      </li>
      <li>
        Since <tt>view.$(selector)</tt> is now equivalent to <tt>view.$el.find(selector)</tt>
        rather than <tt>$(selector, view.el)</tt> it can no longer be used when
        <tt>selector</tt> is an HTML string or DOM element.
      </li>
    </ul>

    <h2 id="Events">Backbone.Events</h2>

    <p>
      <b>Events</b> is a module that can be mixed in to any object, giving the
      object the ability to bind and trigger custom named events. Events do not
      have to be declared before they are bound, and may take passed arguments.
      For example:
    </p>

<pre class="runnable">
var object = {};

_.extend(object, Backbone.Events);

object.on("alert", function(msg) {
  alert("Triggered " + msg);
});

object.trigger("alert", "an event");
</pre>

    <p>
      For example, to make a handy event dispatcher that can coordinate events
      among different areas of your application: <tt>var dispatcher = _.clone(Backbone.Events)</tt>
    </p>

    <p id="Events-on">
      <b class="header">on</b><code>object.on(event, callback, [context])</code><span class="alias">Alias: bind</span>
      <br />
      Bind a <b>callback</b> function to an object. The callback will be invoked
      whenever the <b>event</b> is fired.
      If you have a large number of different events on a page, the convention is to use colons to
      namespace them: <tt>"poll:start"</tt>, or <tt>"change:selection"</tt>.
      The event string may also be a space-delimited list of several events...
    </p>

<pre>
book.on("change:title change:author", ...);
</pre>

    <p>
      To supply a <b>context</b> value for <tt>this</tt> when the callback is invoked,
      pass the optional third argument: <tt>model.on('change', this.render, this)</tt>
    </p>

    <p>
      Callbacks bound to the special
      <tt>"all"</tt> event will be triggered when any event occurs, and are passed
      the name of the event as the first argument. For example, to proxy all events
      from one object to another:
    </p>

<pre>
proxy.on("all", function(eventName) {
  object.trigger(eventName);
});
</pre>

    <p id="Events-off">
      <b class="header">off</b><code>object.off([event], [callback], [context])</code><span class="alias">Alias: unbind</span>
      <br />
      Remove a previously-bound <b>callback</b> function from an object. If no
      <b>context</b> is specified, all of the versions of the callback with
      different contexts will be removed. If no
      callback is specified, all callbacks for the <b>event</b> will be
      removed. If no event is specified, callbacks for <i>all</i> events
      will be removed.
    </p>

<pre>
// Removes just the `onChange` callback.
object.off("change", onChange);

// Removes all "change" callbacks.
object.off("change");

// Removes the `onChange` callback for all events.
object.off(null, onChange);

// Removes all callbacks for `context` for all events.
object.off(null, null, context);

// Removes all callbacks on `object`.
object.off();
</pre>

    <p>
      Note that calling <tt>model.off()</tt>, for example, will indeed remove <i>all</i> events
      on the model &mdash; including events that Backbone uses for internal bookkeeping.
    </p>

    <p id="Events-trigger">
      <b class="header">trigger</b><code>object.trigger(event, [*args])</code>
      <br />
      Trigger callbacks for the given <b>event</b>, or space-delimited list of events.
      Subsequent arguments to <b>trigger</b> will be passed along to the
      event callbacks.
    </p>

    <p id="Events-catalog">
      <b class="header">Catalog of Events</b>
      <br />
      Here's the complete list of built-in Backbone events, with arguments.
      You're also free to trigger your own events on Models, Collections and
      Views as you see fit.
    </p>

    <ul class="small">
      <li><b>"add"</b> (model, collection, options) &mdash; when a model is added to a collection. </li>
      <li><b>"remove"</b> (model, collection, options) &mdash; when a model is removed from a collection. </li>
      <li><b>"reset"</b> (collection, options) &mdash; when the collection's entire contents have been replaced. </li>
      <li><b>"change"</b> (model, options) &mdash; when a model's attributes have changed. </li>
      <li><b>"change:[attribute]"</b> (model, value, options) &mdash; when a specific attribute has been updated. </li>
      <li><b>"destroy"</b> (model, collection, options) &mdash; when a model is <a href="#Model-destroy">destroyed</a>. </li>
      <li><b>"sync"</b> (model, resp, options) &mdash; triggers whenever a model has been successfully synced to the server. </li>
      <li><b>"error"</b> (model, collection) &mdash; when a model's validation fails, or a <a href="#Model-save">save</a> call fails on the server. </li>
      <li><b>"route:[name]"</b> (router) &mdash; when one of a router's routes has matched. </li>
      <li><b>"all"</b> &mdash; this special event fires for <i>any</i> triggered event, passing the event name as the first argument. </li>
    </ul>

    <h2 id="Model">Backbone.Model</h2>

    <p>
      <b>Models</b> are the heart of any JavaScript application, containing
      the interactive data as well as a large part of the logic surrounding it:
      conversions, validations, computed properties, and access control. You
      extend <b>Backbone.Model</b> with your domain-specific methods, and
      <b>Model</b> provides a basic set of functionality for managing changes.
    </p>

    <p>
      The following is a contrived example, but it demonstrates defining a model
      with a custom method, setting an attribute, and firing an event keyed
      to changes in that specific attribute.
      After running this code once, <tt>sidebar</tt> will be
      available in your browser's console, so you can play around with it.
    </p>

<pre class="runnable">
var Sidebar = Backbone.Model.extend({
  promptColor: function() {
    var cssColor = prompt("Please enter a CSS color:");
    this.set({color: cssColor});
  }
});

window.sidebar = new Sidebar;

sidebar.on('change:color', function(model, color) {
  $('#sidebar').css({background: color});
});

sidebar.set({color: 'white'});

sidebar.promptColor();
</pre>

    <p id="Model-extend">
      <b class="header">extend</b><code>Backbone.Model.extend(properties, [classProperties])</code>
      <br />
      To create a <b>Model</b> class of your own, you extend <b>Backbone.Model</b>
      and provide instance <b>properties</b>, as well as optional
      <b>classProperties</b> to be attached directly to the constructor function.
    </p>

    <p>
      <b>extend</b> correctly sets up the prototype chain, so subclasses created
      with <b>extend</b> can be further extended and subclassed as far as you like.
    </p>

<pre>
var Note = Backbone.Model.extend({

  initialize: function() { ... },

  author: function() { ... },

  coordinates: function() { ... },

  allowedToEdit: function(account) {
    return true;
  }

});

var PrivateNote = Note.extend({

  allowedToEdit: function(account) {
    return account.owns(this);
  }

});
</pre>

    <p class="warning">
        Brief aside on <tt>super</tt>: JavaScript does not provide
        a simple way to call super &mdash; the function of the same name defined
        higher on the prototype chain. If you override a core function like
        <tt>set</tt>, or <tt>save</tt>, and you want to invoke the
        parent object's implementation, you'll have to explicitly call it, along these lines:
    </p>

<pre>
var Note = Backbone.Model.extend({
  set: function(attributes, options) {
    Backbone.Model.prototype.set.apply(this, arguments);
    ...
  }
});
</pre>

    <p id="Model-constructor">
      <b class="header">constructor / initialize</b><code>new Model([attributes], [options])</code>
      <br />
      When creating an instance of a model, you can pass in the initial values
      of the <b>attributes</b>, which will be <a href="#Model-set">set</a> on the
      model. If you define an <b>initialize</b> function, it will be invoked when
      the model is created.
    </p>

<pre>
new Book({
  title: "One Thousand and One Nights",
  author: "Scheherazade"
});
</pre>

    <p>
      In rare cases, if you're looking to get fancy,
      you may want to override <b>constructor</b>, which allows
      you to replace the actual constructor function for your model.
    </p>

    <p>
      If you pass a <tt>{collection: ...}</tt> as the <b>options</b>, the model
      gains a <tt>collection</tt> property that will be used to indicate which
      collection the model belongs to, and is used to help compute the model's
      <a href="#Model-url">url</a>. The <tt>model.collection</tt> property is
      otherwise added automatically when you first add a model to a collection.
    </p>

    <p id="Model-get">
      <b class="header">get</b><code>model.get(attribute)</code>
      <br />
      Get the current value of an attribute from the model. For example:
      <tt>note.get("title")</tt>
    </p>

    <p id="Model-set">
      <b class="header">set</b><code>model.set(attributes, [options])</code>
      <br />
      Set a hash of attributes (one or many) on the model. If any of the attributes
      change the model's state, a <tt>"change"</tt> event will be triggered, unless
      <tt>{silent: true}</tt> is passed as an option. Change events for specific
      attributes are also triggered, and you can bind to those as well, for example:
      <tt>change:title</tt>, and <tt>change:content</tt>. You may also pass
      individual keys and values.
    </p>

<pre>
note.set({title: "March 20", content: "In his eyes she eclipses..."});

book.set("title", "A Scandal in Bohemia");
</pre>

    <p>
      If the model has a <a href="#Model-validate">validate</a> method,
      it will be validated before the attributes are set, no changes will
      occur if the validation fails, and <b>set</b> will return <tt>false</tt>.
      Otherwise, <b>set</b> returns a reference to the model.
      You may also pass an <tt>error</tt>
      callback in the options, which will be invoked instead of triggering an
      <tt>"error"</tt> event, should validation fail.
    </p>

    <p>
      Passing <tt>{silent: true}</tt> as an option will defer both the validation
      and the event. This is useful when you want to
      change attributes provisionally or rapidly, without propagating the change
      through the rest of the system. That said, <tt>silent</tt> doesn't mean that
      the change (and event) won't happen, it's merely silenced until the next
      <a href="#Model-change">change</a>.
    </p>

    <p id="Model-escape">
      <b class="header">escape</b><code>model.escape(attribute)</code>
      <br />
      Similar to <a href="#Model-get">get</a>, but returns the HTML-escaped version
      of a model's attribute. If you're interpolating data from the model into
      HTML, using <b>escape</b> to retrieve attributes will prevent
      <a href="http://en.wikipedia.org/wiki/Cross-site_scripting">XSS</a> attacks.
    </p>

<pre class="runnable">
var hacker = new Backbone.Model({
  name: "&lt;script&gt;alert('xss')&lt;/script&gt;"
});

alert(hacker.escape('name'));
</pre>

    <p id="Model-has">
      <b class="header">has</b><code>model.has(attribute)</code>
      <br />
      Returns <tt>true</tt> if the attribute is set to a non-null or non-undefined
      value.
    </p>

<pre>
if (note.has("title")) {
  ...
}
</pre>

    <p id="Model-unset">
      <b class="header">unset</b><code>model.unset(attribute, [options])</code>
      <br />
      Remove an attribute by deleting it from the internal attributes hash.
      Fires a <tt>"change"</tt> event unless <tt>silent</tt> is passed as an option.
    </p>

    <p id="Model-clear">
      <b class="header">clear</b><code>model.clear([options])</code>
      <br />
      Removes all attributes from the model, including the <tt>id</tt> attribute. Fires a <tt>"change"</tt> event unless
      <tt>silent</tt> is passed as an option.
    </p>

    <p id="Model-id">
      <b class="header">id</b><code>model.id</code>
      <br />
      A special property of models, the <b>id</b> is an arbitrary string
      (integer id or UUID). If you set the <b>id</b> in the
      attributes hash, it will be copied onto the model as a direct property.
      Models can be retrieved by id from collections, and the id is used to generate
      model URLs by default.
    </p>

    <p id="Model-idAttribute">
      <b class="header">idAttribute</b><code>model.idAttribute</code>
      <br />
      A model's unique identifier is stored under the <tt>id</tt> attribute.
      If you're directly communicating with a backend (CouchDB, MongoDB) that uses
      a different unique key, you may set a Model's <tt>idAttribute</tt> to
      transparently map from that key to <tt>id</tt>.

<pre class="runnable">
var Meal = Backbone.Model.extend({
  idAttribute: "_id"
});

var cake = new Meal({ _id: 1, name: "Cake" });
alert("Cake id: " + cake.id);
</pre>
    </p>

    <p id="Model-cid">
      <b class="header">cid</b><code>model.cid</code>
      <br />
      A special property of models, the <b>cid</b> or client id is a unique identifier
      automatically assigned to all models when they're first created. Client ids
      are handy when the model has not yet been saved to the server, and does not
      yet have its eventual true <b>id</b>, but already needs to be visible in the UI.
      Client ids take the form: <tt>c1, c2, c3 ...</tt>
    </p>

    <p id="Model-attributes">
      <b class="header">attributes</b><code>model.attributes</code>
      <br />
      The <b>attributes</b> property is the internal hash containing the model's
      state &mdash; usually (but not necessarily) a form of the JSON object
      representing the model data on the server. It's often a straightforward
      serialization of a row from the database, but it could also be client-side
      computed state.
    </p>

    <p>
      Please use <a href="#Model-set">set</a> to update the <b>attributes</b>
      instead of modifying them directly. If you'd like to retrieve and munge a
      copy of the model's attributes, use <a href="#Model-toJSON">toJSON</a>
      instead.
    </p>

    <p class="warning">
      Due to the fact that <a href="#Events">Events</a> accepts space separated
      lists of events, attribute names should not include spaces.
    </p>

    <p id="Model-changed">
      <b class="header">changed</b><code>model.changed</code>
      <br />
      The <b>changed</b> property is the internal hash containing all the attributes
      that have changed since the last <tt>"change"</tt> event was triggered.
      Please do not update <b>changed</b> directly.  Its state is maintained internally
      by <a href="#Model-set">set</a> and <a href="#Model-change">change</a>.
      A copy of <b>changed</b> can be acquired from
      <a href="#Model-changedAttributes">changedAttributes</a>.
    </p>

    <p id="Model-defaults">
      <b class="header">defaults</b><code>model.defaults or model.defaults()</code>
      <br />
      The <b>defaults</b> hash (or function) can be used to specify the default
      attributes for your model. When creating an instance of the model,
      any unspecified attributes will be set to their default value.
    </p>

<pre class="runnable">
var Meal = Backbone.Model.extend({
  defaults: {
    "appetizer":  "caesar salad",
    "entree":     "ravioli",
    "dessert":    "cheesecake"
  }
});

alert("Dessert will be " + (new Meal).get('dessert'));
</pre>

    <p class="warning">
      Remember that in JavaScript, objects are passed by reference, so if you
      include an object as a default value, it will be shared among all instances.
      Instead, define <b>defaults</b> as a function.
    </p>

    <p id="Model-toJSON">
      <b class="header">toJSON</b><code>model.toJSON()</code>
      <br />
      Return a copy of the model's <a href="#Model-attributes">attributes</a> for JSON stringification.
      This can be used for persistence, serialization, or for augmentation before
      being handed off to a view. The name of this method is a bit confusing, as
      it doesn't actually return a JSON string &mdash; but I'm afraid that it's
      the way that the <a href="https://developer.mozilla.org/en/JSON#toJSON()_method">JavaScript API for <b>JSON.stringify</b> works</a>.
    </p>

<pre class="runnable">
var artist = new Backbone.Model({
  firstName: "Wassily",
  lastName: "Kandinsky"
});

artist.set({birthday: "December 16, 1866"});

alert(JSON.stringify(artist));
</pre>

    <p id="Model-sync">
      <b class="header">sync</b><code>model.sync(method, model, [options])</code>
      <br />
      Uses <a href="#Sync">Backbone.sync</a> to persist the state of a model to
      the server.  Can be overridden for custom behavior.
    </p>

    <p id="Model-fetch">
      <b class="header">fetch</b><code>model.fetch([options])</code>
      <br />
      Resets the model's state from the server by delegating to
      <a href="#Sync">Backbone.sync</a>. Returns a
      <a href="http://api.jquery.com/jQuery.ajax/#jqXHR">jqXHR</a>.
      Useful if the model has never
      been populated with data, or if you'd like to ensure that you have the
      latest server state. A <tt>"change"</tt> event will be triggered if the
      server's state differs from the current attributes. Accepts
      <tt>success</tt> and <tt>error</tt> callbacks in the options hash, which
      are passed <tt>(model, response, options)</tt>
      and <tt>(model, xhr, options)</tt> as arguments, respectively.
    </p>

<pre>
// Poll every 10 seconds to keep the channel model up-to-date.
setInterval(function() {
  channel.fetch();
}, 10000);
</pre>

    <p id="Model-save">
      <b class="header">save</b><code>model.save([attributes], [options])</code>
      <br />
      Save a model to your database (or alternative persistence layer),
      by delegating to <a href="#Sync">Backbone.sync</a>.  Returns a
      <a href="http://api.jquery.com/jQuery.ajax/#jqXHR">jqXHR</a> if
      validation is successful and <tt>false</tt> otherwise. The <b>attributes</b>
      hash (as in <a href="#Model-set">set</a>) should contain the attributes
      you'd like to change &mdash; keys that aren't mentioned won't be altered &mdash; but,
      a <i>complete representation</i> of the resource will be sent to the server.
      As with <tt>set</tt>, you may pass individual keys and values instead of a hash.
      If the model has a <a href="#Model-validate">validate</a>
      method, and validation fails, the model will not be saved. If the model
      <a href="#Model-isNew">isNew</a>, the save will be a <tt>"create"</tt>
      (HTTP <tt>POST</tt>), if the model already
      exists on the server, the save will be an <tt>"update"</tt> (HTTP <tt>PUT</tt>).
    </p>

    <p>
      Calling <tt>save</tt> with new attributes will cause a <tt>"change"</tt>
      event immediately, and a <tt>"sync"</tt> event after the server has acknowledged
      the successful change. Pass <tt>{wait: true}</tt> if you'd like to wait
      for the server before setting the new attributes on the model.
    </p>

    <p>
      In the following example, notice how our overridden version
      of <tt>Backbone.sync</tt> receives a <tt>"create"</tt> request
      the first time the model is saved and an <tt>"update"</tt>
      request the second time.
    </p>

<pre class="runnable">
Backbone.sync = function(method, model) {
  alert(method + ": " + JSON.stringify(model));
  model.id = 1;
};

var book = new Backbone.Model({
  title: "The Rough Riders",
  author: "Theodore Roosevelt"
});

book.save();

book.save({author: "Teddy"});
</pre>

    <p>
      <b>save</b> accepts <tt>success</tt> and <tt>error</tt> callbacks in the
      options hash, which are passed <tt>(model, response, options)</tt> and
      <tt>(model, xhr, options)</tt> as arguments, respectively.
      The <tt>error</tt> callback will also be invoked if the model has a
      <tt>validate</tt> method, and validation fails. If a server-side
      validation fails, return a non-<tt>200</tt> HTTP response code, along with
      an error response in text or JSON.
    </p>

<pre>
book.save("author", "F.D.R.", {error: function(){ ... }});
</pre>

    <p id="Model-destroy">
      <b class="header">destroy</b><code>model.destroy([options])</code>
      <br />
      Destroys the model on the server by delegating an HTTP <tt>DELETE</tt>
      request to <a href="#Sync">Backbone.sync</a>. Returns a
      <a href="http://api.jquery.com/jQuery.ajax/#jqXHR">jqXHR</a> object, or
      <tt>false</tt> if the model <a href="#Model-isNew">isNew</a>. Accepts
      <tt>success</tt> and <tt>error</tt> callbacks in the options hash, which
      are passed <tt>(model, response, options)</tt> and <tt>(model, xhr, options)</tt>
      as arguments, respectively.
      Triggers a <tt>"destroy"</tt> event on the model, which will bubble up
      through any collections that contain it, and a <tt>"sync"</tt> event, after
      the server has successfully acknowledged the model's deletion. Pass
      <tt>{wait: true}</tt> if you'd like to wait for the server to respond
      before removing the model from the collection.
    </p>

<pre>
book.destroy({success: function(model, response) {
  ...
}});
</pre>

    <p id="Model-validate">
      <b class="header">validate</b><code>model.validate(attributes)</code>
      <br />
      This method is left undefined, and you're encouraged to override it with
      your custom validation logic, if you have any that can be performed
      in JavaScript. <b>validate</b> is called before <tt>set</tt> and
      <tt>save</tt>, and is passed the model attributes updated with the values
      from <tt>set</tt> or <tt>save</tt>.
      If the attributes are valid, don't return anything from <b>validate</b>;
      if they are invalid, return an error of your choosing. It
      can be as simple as a string error message to be displayed, or a complete
      error object that describes the error programmatically. If <b>validate</b>
      returns an error, <tt>set</tt> and <tt>save</tt> will not continue, and the
      model attributes will not be modified.
      Failed validations trigger an <tt>"error"</tt> event.
    </p>

<pre class="runnable">
var Chapter = Backbone.Model.extend({
  validate: function(attrs) {
    if (attrs.end < attrs.start) {
      return "can't end before it starts";
    }
  }
});

var one = new Chapter({
  title : "Chapter One: The Beginning"
});

one.on("error", function(model, error) {
  alert(model.get("title") + " " + error);
});

one.set({
  start: 15,
  end:   10
});
</pre>

    <p>
      <tt>"error"</tt> events are useful for providing coarse-grained error
      messages at the model or collection level, but if you have a specific view
      that can better handle the error, you may override and suppress the event
      by passing an <tt>error</tt> callback directly:
    </p>

<pre>
account.set({access: "unlimited"}, {
  error: function(model, error) {
    alert(error);
  }
});
</pre>

    <p id="Model-isValid">
      <b class="header">isValid</b><code>model.isValid()</code>
      <br />
      Models may enter an invalid state if you make changes to them silently
      ... useful when dealing with form input. Call <tt>model.isValid()</tt>
      to check if the model is currently in a valid state, according to your
      <tt>validate</tt> function.
    </p>

    <p id="Model-url">
      <b class="header">url</b><code>model.url()</code>
      <br />
      Returns the relative URL where the model's resource would be located on
      the server. If your models are located somewhere else, override this method
      with the correct logic. Generates URLs of the form: <tt>"/[collection.url]/[id]"</tt>
      by default, but you may override by specifying an explicit <tt>urlRoot</tt>
      if the model's collection shouldn't be taken into account.
    </p>

    <p>
      Delegates to <a href="#Collection-url">Collection#url</a> to generate the
      URL, so make sure that you have it defined, or a <a href="#Model-urlRoot">urlRoot</a>
      property, if all models of this class share a common root URL.
      A model with an id of <tt>101</tt>, stored in a
      <a href="#Collection">Backbone.Collection</a> with a <tt>url</tt> of <tt>"/documents/7/notes"</tt>,
      would have this URL: <tt>"/documents/7/notes/101"</tt>
    </p>

    <p id="Model-urlRoot">
      <b class="header">urlRoot</b><code>model.urlRoot or model.urlRoot()</code>
      <br />
      Specify a <tt>urlRoot</tt> if you're using a model <i>outside</i> of a collection,
      to enable the default <a href="#Model-url">url</a> function to generate
      URLs based on the model id. <tt>"/[urlRoot]/id"</tt><br />
      Normally, you won't need to define this.
      Note that <tt>urlRoot</tt> may also be a function.
    </p>

<pre class="runnable">
var Book = Backbone.Model.extend({urlRoot : '/books'});

var solaris = new Book({id: "1083-lem-solaris"});

alert(solaris.url());
</pre>

    <p id="Model-parse">
      <b class="header">pars…
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