title: Javascript setdate getDate()+28 returns bad
body: <p>I am getting a weird output when trying to add days to a date value. </p>
  
  <pre><code>var startdate = $("#JobStartDate").val();
  
  startdate = new Date(startdate);
  startdate28 = startdate.setDate(startdate.getDate()+28);
  
  console.log(startdate);
  console.log(startdate28);
  </code></pre>
  
  <p>results in </p>
  
  <pre><code>startdate = "Date 2017-03-15T00:00:00.000Z"
  
  startdate28 = 1489536000000
  </code></pre>
  
  <p>any ideas where i am going wrong?</p>