title: jQuery selector for the child of a parent's previous sibling
body: <p>For each stat block like the following:</p>
  
  <pre><code>&lt;div class="stats"&gt;
    &lt;div class="label"&gt;
      &lt;span class="goal"&gt;10 YEARS OF SOMETHING GOOD&lt;/span&gt;
    &lt;/div&gt;
    &lt;div class="stat"&gt;
      &lt;div class="tri"&gt;&lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to set the marginRight of <code>tri</code> to half the width of the previous <code>goal</code>.  Which jQuery selector would I use to grab the previous 'goal' relative to each <code>tri</code> ?</p>
  
  <p>Something like..</p>
  
  <pre><code>$(function(){
    $('.tri').css({marginRight: function() {
      return Math.floor($(this).something('.goal').width() / 2) + 'px';
    }})
  })
  </code></pre>