title: Given a specific td, get td value from the top row of same column using Jquery
body: <p>Title says it all.  I have a table that is a list of dates across the top tr.  Clicking a specific td, I want to be able to get the td value from the top row of same column using Jquery.</p>
  
  <p>For example:</p>
  
  <pre><code>&lt;table&gt;
    &lt;tr&gt;
       &lt;td&gt;Jan 1&lt;/td&gt;
       &lt;td&gt;Jan 2&lt;/td&gt;
       &lt;td&gt;Jan 3&lt;/td&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
       &lt;td&gt;col 1, row 1&lt;/td&gt;
       &lt;td&gt;col 2, row 1&lt;/td&gt;
       &lt;td&gt;col 3, row 1&lt;/td&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
       &lt;td&gt;col 1, row 2&lt;/td&gt;
       &lt;td&gt;col 2, row 2&lt;/td&gt;
       &lt;td&gt;col 3, row 2&lt;/td&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
       &lt;td&gt;col 1, row 3&lt;/td&gt;
       &lt;td&gt;col 2, row 3&lt;/td&gt;
       &lt;td&gt;col 3, row 3&lt;/td&gt;
    &lt;/tr&gt;
  </code></pre>
  
  <p></p>
  
  <p>If I click any of the td's in col 1 I want to return the value "Jan 1"</p>
  
  <p>If I click any of the td's in col 2 I want to return the value "Jan 2"</p>
  
  <p>If I click any of the td's in col 3 I want to return the value "Jan 3"</p>
  
  <p>Make sense?</p>
  
  <p>Currently, I only want this to happen for empty td's so here's the start of my jQuery.</p>
  
  <pre><code>$("table td:empty").dblclick(function(){
  
    $(TD VALUE FROM TOP OF SAME COLUMN).text();
  
  });
  </code></pre>