title: How do I subtract minutes from a date in JavaScript?
body: <p>How can I translate this pseudo code into working JS [don't worry about where the end date comes from except that it's a valid JavaScript date].</p>
  <pre><code>var myEndDateTime = somedate;  //somedate is a valid JS date  
  var durationInMinutes = 100; //this can be any number of minutes from 1-7200 (5 days)
  
  //this is the calculation I don't know how to do
  var myStartDate = somedate - durationInMinutes;
  
  alert(&quot;The event will start on &quot; + myStartDate.toDateString() + &quot; at &quot; + myStartDate.toTimeString());
  </code></pre>