title: Finding nth-child of siblings via jQuery
body: <p>Let's say I have two tables that look like this:</p>
  
  <pre><code>TH   TH   TH   TH  
  TD   TD   TD   TD  
  TD   TD   TD   TD  
  </code></pre>
  
  <p>and</p>
  
  <pre><code>TH   TH   TH   TH  
  TH   TD   TD   TD  
  TH   TD   TD   TD  
  </code></pre>
  
  <p>I'd like to select the 3rd column in each.</p>
  
  <p>At first I was using nth-child as such:</p>
  
  <pre><code>$('table tr td:nth-child(3)')
  </code></pre>
  
  <p>But that's not going to work, as 3rd TD is in a different column in each table.</p>
  
  <p>What I need in pseudo code is 'get the 3rd TD <em>or</em> TH in each row'.</p>
  
  <p>I assume I need to use $.siblings but not entirely sure.</p>