title: jQuery: isotope sorting by date
body: <p>I'm sorting a grid of divs by date, but I've encountered a problem. The divs are being sorted by date, but when you introduce another month, it doesn't take that into account and just sorts by the day value.<br><br>
  HTML: </p>
  
  <pre><code>&lt;div class="grid-filter"&gt;
      &lt;a href="#"&gt;
      &lt;div class="grid-block" style="background-color: #46747c" data-category="1952013"&gt;
          &lt;div class="block-text date-title"&gt;19/05&lt;/div&gt;
      &lt;/div&gt;
      &lt;/a&gt;
  &lt;/div&gt;
  &lt;div class="grid-filter"&gt;
      &lt;a href="#"&gt;
      &lt;div class="grid-block" style="background-color: #ebd133" data-category="2552013"&gt;
          &lt;div class="block-text date-title"&gt;25/05&lt;/div&gt;
      &lt;/div&gt;
      &lt;/a&gt;
  &lt;/div&gt;
  &lt;div class="grid-filter"&gt;
      &lt;a href="#"&gt;
      &lt;div class="grid-block" style="background-color: #cc7788" data-category="3052013"&gt;
          &lt;div class="block-text date-title"&gt;30/05&lt;/div&gt;
      &lt;/div&gt;
      &lt;/a&gt;
  &lt;/div&gt;
  &lt;div class="grid-filter"&gt;
      &lt;a href="#"&gt;
      &lt;div class="grid-block" style="background-color: #46747c" data-category="0562013"&gt;
          &lt;div class="block-text date-title"&gt;05/06&lt;/div&gt;
      &lt;/div&gt;
      &lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><br>
  jQuery</p>
  
  <pre><code> jQuery(document).ready(function(){
  
  var jQuerycontainer = jQuery('#main-grid');
  
  if(location.hash!=""){
      var hashfilter = "." + location.hash.substr(1);
      }
      else{
      var hashfilter = "*";
      }
  
  jQuerycontainer.imagesLoaded( function(){
  jQuerycontainer.isotope({
      filter: hashfilter,
      itemSelector: '.grid-block',
      getSortData : {
      date : function( jQueryelem ) {
      return jQueryelem.attr('data-category');
      }
      },
      sortBy : 'date',
      animationEngine: 'css',
      masonry: {
      columnWidth: 4
      }
  
  });
  });
  
  jQuery('.filter-menu a').click(function(){
      var selector = jQuery(this).attr('data-filter');
      var prettyselector = selector.substr(1);
      location.hash = prettyselector;
      jQuery('html, body').animate({scrollTop:0}, 'slow');
      return false;
      });
  
  jQuery('.grid-filter a').click(function(){
      var selector = jQuery(this).attr('data-filter');
      var prettyselector = selector.substr(1);
      location.hash = prettyselector;
      jQuery('html, body').animate({scrollTop:0}, 'slow');
      return false;
      }); 
  
  jQuery(window).hashchange(function(){
  
                  if(location.hash!=""){
                      var hashfilter = "." + location.hash.substr(1);
                  }
                  else{
                      var hashfilter = "*";
                  }
  
  
  jQuerycontainer.imagesLoaded( function(){
  jQuerycontainer.isotope({
      filter: hashfilter,
      itemSelector: '.grid-block',
      getSortData : {
      date : function( jQueryelem ) {
      return jQueryelem.attr('data-category');
      }
      },
      sortBy : 'date',
      animationEngine: 'css',
      masonry: {
      columnWidth: 4
      }
  });
  });
  });
  });
  </code></pre>
  
  <p>So the blocks are being sorted, BUT the final one with the date <code>0562013</code> is appearing first as 05 is the smallest number I assume, is there anyway to take the month into account also so it will successfully sort the divs by date?</p>