title: OADate to Milliseconds timestamp in Javascript
body: <p>I try to do the exact opposite of :</p>
  
  <p><a href="https://stackoverflow.com/questions/7348805/what-is-equivalent-of-datetime-tooadate-in-javascript">What is equivalent of DateTime.ToOADate() in javascript?</a></p>
  
  <p>Create a millisecond date (number of milliseconds since 1/1/1970)  from a OADate (number of  days since 30 dec 1899 as a double value)</p>
  
  <p>my guess is I can do like this :</p>
  
  <pre><code>this.unixTimeStampFromOADate = function( OADateFloat)
  {
          var oaDateFor1970 = ?? ; //what's the value for 1/1/1970 in OADate format ?
          var delta = Math.floor(OADateFloat - oaDateFor1970);
  
          return delta*(1000*60*60*24); 
  }
  </code></pre>
  
  <p>so if I'm right, I need the value for 1/1/1970 in OADate format.
  if I'm wrong, please can you suggest another conversion method ?</p>