docs : add hash history with jQuery BBQ

ten gallon hat tip @cowboy

_posts/docs/2011-06-16-hash-history-jquery-bbq.mdown

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+---
+
+title: Hash history with jQuery BBQ
+category: docs
+layout: default
+toc:
+  - { title: Markup, anchor: markup }
+  - { title: jQuery script, anchor: jquery_script }
+
+---
+
+As cool as Isotope is, the only thing that could make it even cooler would be adding bookmark-able URL hashes. Ben Alman's [jQuery BBQ](http://benalman.com/projects/jquery-bbq-plugin/) allows us to do just that.
+
+> jQuery BBQ leverages the HTML5 hashchange event to allow simple, yet powerful bookmarkable #hash history.
+
+[**See Demo: Hash history**](../demos/hash-history.html)
+
+BBQ is a marvelous plugin that provides for a lot more functionality. The [hash history demo](../demos/hash-history.html) uses multiple options (`sortBy`, `sortAscending`, and `layoutMode` in addition to `filter`), the ability to use back-button history, and properly highlights selected links.
+
+Given BBQ's tremendous capabilities, the code can grow to be a bit complex. Be sure to read through [BBQ's docs](http://benalman.com/code/projects/jquery-bbq/docs/files/jquery-ba-bbq-js.html) and take look at [its examples](http://benalman.com/code/projects/jquery-bbq/examples/) before you dive in and code up your own solution.
+
+## Markup
+
+Instead of setting the option values and keys with `data` attributes, we can add the option in the `href` for each link.
+
+{% highlight html %}
+
+<ul class="option-set">
+  <li><a href="#filter=*" class="selected">show all</a></li>
+  <li><a href="#filter=.metal">metal</a></li>
+  <li><a href="#filter=.transition">transition</a></li>
+  <li><a href="#filter=.alkali%2C+.alkaline-earth">alkali and alkaline-earth</a></li>
+  <li><a href="#filter=%3Anot(.transition)">not transition</a></li>
+  <li><a href="#filter=.metal%3Anot(.transition)">metal but not transition</a></li>
+</ul>
+
+{% endhighlight %}
+
+The `href` value is a serialized string, suitable for a URL. These values can be created with [jQuery.param()](http://api.jquery.com/jQuery.param/).
+
+{% highlight javascript %}
+
+$.param({ filter: '.metal' })
+// >> "filter=.metal"
+$.param({ filter: '.alkali, alkaline-earth' })
+// >> "filter=.alkali%2C+alkaline-earth"
+$.param({ filter: ':not(.transition)' })
+// >> "#filter=%3Anot(.transition)"
+
+{% endhighlight %}
+
+## jQuery script
+
+These serialized `href` values can be converted into their proper jQuery object form when clicked using  [jQuery.deparam()](http://benalman.com/code/projects/jquery-bbq/docs/files/jquery-ba-bbq-js.html#jQuery.deparam) from jQuery BBQ.
+
+{% highlight javascript %}
+
+$('.option-set a').click(function(){
+      // get href attr, remove leading #
+  var href = $(this).attr('href').replace( /^#/, '' ),
+      // convert href into object
+      // i.e. 'filter=.inner-transition' -> { filter: '.inner-transition' }
+      option = $.deparam( href, true );
+  // set hash, triggers hashchange on window
+  $.bbq.pushState( option );
+  return false;
+});
+
+{% endhighlight %}
+
+Calling [$.bbq.pushState()](http://benalman.com/code/projects/jquery-bbq/docs/files/jquery-ba-bbq-js.html#jQuery.bbq.pushState) will trigger the `hashchange` event. At that point, we can parse the hash from the URL and use it to trigger the proper change in the Isotope instance.
+
+{% highlight javascript %}
+
+$(window).bind( 'hashchange', function( event ){
+  // get options object from hash
+  var hashOptions = $.deparam.fragment();
+  // apply options from hash
+  $container.isotope( hashOptions );
+})
+  // trigger hashchange to capture any hash data on init
+  .trigger('hashchange');
+
+{% endhighlight %}
+
+Now any filter buttons that are clicked will update the URL hash, so these options can be bookmarked.