title: Add class to parent and sibling elements if element with specific class is found
body: <p>Given the following HTML:</p>
  
  <pre><code>&lt;div class="row"&gt;
      &lt;label class="label"&gt;Label Text&lt;/label&gt;
      &lt;div class="error"&gt;Error Message&lt;/div&gt;
      &lt;div class="container"&gt;
          &lt;input type="text" class="input"&gt;
      &lt;/div&gt;
      &lt;div class="instructions"&gt;
          Instructions text
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Obviously, this is repeated for each form field, except that the <code>div.error</code> is only present for such rows as actually contain errors (validated serverside).</p>
  
  <p>If the <code>row</code> includes a <code>div.error</code>, then I want to use jQuery to assign additional classes to the <code>.row</code>, <code>.label</code>, <code>.input</code>, and <code>.instructions</code> classes -- but ONLY for the <code>div.row</code> that includes the error.</p>
  
  <p>(I realize jQuery is not the best way to handle this, but all I have under the circumstances.)</p>
  
  <p>I've tied my brain in knots for the past two hours and just can't figure it out, so would appreciate any answers on how this can be accomplished.</p>