title: subtract time from date - moment js
body: <p>I have for instance this datetime: </p>
  
  <pre><code>01:20:00 06-26-2014
  </code></pre>
  
  <p>and I want to subtract a time like this:</p>
  
  <pre><code>00:03:15
  </code></pre>
  
  <p>after that I'd like to format the result like this:</p>
  
  <p><code>3 hours and 15 minutes earlier</code>.</p>
  
  <p>How can I do that using <code>moment.js</code> ?</p>
  
  <p><strong>edit</strong>: I tried:</p>
  
  <pre><code>var time = moment( "00:03:15" );
  var date = moment( "2014-06-07 09:22:06" );
  
  date.subtract (time); 
  </code></pre>
  
  <p>but the result is the same as <code>date</code></p>
  
  <p>Thanks</p>