title: Converting isodate to numerical value
body: <p>I am performing tests to ensure I'm getting the dates correctly.</p>
  
  <p>My current tests are: pick a date in mongodb ISODate format and transform it to the numerical value (milliseconds since 1970) and vice versa</p>
  
  <p>Example:</p>
  
  <pre><code>var date_test = ISODate ("2013-07-26T22:35:40.373Z")
  </code></pre>
  
  <p>What is the numeric value of this date? Which command is used to get this?</p>